I woke up thinking about this. My first thought when I saw the bed/cabinet/headstock was that this could be a way to have a working Heavy 10 for well under a thousand bucks, given some luck. But I'm projecting what I'd be willing to do, and a best case scenario, which is that the ways are in great shape. Some sellers know what it means for ways to be in great shape, others just mean they LOOK great because there aren't big chips and holes in them, or they aren't covered in pitted rust.
The worst case scenario deserves consideration, though. Let's say the bed is really worn. If the bed is heavily worn, it will be impossible to scrape a new saddle to fit -- the ways will be thinner down by the chuck and thicker back by the tail stock, so that gibs adjusted for a good fit down by the chuck will be too tight for machining a long shaft, and vice versa. This is not a problem for pipemakers given a lathe whose parts have grown old together, but it makes Frankensteining a lathe back together difficult. An old saddle would have worn here and there in ways that it would be counterproductive to try to duplicate by hand. And that could be why this lathe is missing its limbs.
The remedy in that case is to send the lathe out for regrinding. There are a couple of shops in the US who still do this work, but I doubt there's one in Texas. What you do is send them all the mating parts -- bed, headstock, saddle, apron, lead screw, tail stock. They surface grind (BIG surface grinder/jigs) all the mating surfaces so that they match perfectly, then adjust parts as necessary -- for instance, if you take .020" off the bed and .015" off the saddle vees, you have to take .035" off the top of the apron or the pinion gear won't engage the bed rack sufficiently and you'll have lots of slop and wear the tips off the teeth. And if you take .020" off the tailstock vees you either have to take that off the headstock or shim up the tail stock or it will be too low. Cost could be between $800 and $1200. The alternative would be to hand scrape everything, which can be and has been done, but that takes skill and experience. Not a good first scraping project. It has to be remembered that a complete Heavy 10 in new condition -- which it would be with a good regrind -- is easily a $3000 machine. The lathe would be a really beautiful thing, just accurate as anything and ready for another 40 years of work. But while the deal may make sense to a machine dealer or lathe freak, starting with $200 and being in for another $500 for a carriage and tail stock and then looking at another thousand for regrinding could really stink for a guy who just wants to make pipes.
An alternative would be to look for a good used bed/saddle, already mated but whose head stock is missing. I've seen those, too. But that's more uncertainty, and approximately 500# of iron sitting in your shop waiting for parts. You'd basically be buying the headstock and cabinet, and shopping for the rest. Prices for Heavy 10 beds/saddles depend, not surprisingly, on condition -- free to a couple hundred. Jeff, the tools4cheap guy, is a good source.
Fair enough -- how do you tell if the bed is worn? Well, if it's a flame hardened bed it shouldn't be worn much unless it was used with abrasives, like for polishing or with a toolpost grinder. But the first thing you look for is a groove along the length of the front V-way. This is where machining forces bear the hardest, and heavy wear will show as a groove that is absent at the ends of the way and deepest right in front of the chuck, where most machining takes place. You can also check with a really good straight edge and feeler gauges, though most straight edges won't qualify for this kind of precision. You can also check for wear using the tail stock with a dial indicator to measure the saddle ways relative to the tail stock ways. Since the two sets of ways wear in different areas, you can use one to check the other if you pick your spots. Of course, with no saddle or tail stock, you can't do that.
Sorry to ramble. Old American iron is regarded by many as the best manual machinery to have, and there are cases where that's true. Almost anything can be fixed. I'll amend that. ANYTHING can be fixed. It's just a question of how deep in you want to get. And whether or not you enjoy being "in" in the first place.
Addendum: looking at the pictures again, I notice the paint is worn off the headstock casting but not off the covers or bearing caps. There may be an explanation for this, but the machine may have *started* as a Frankenstein project and the seller got to a point where he realized his position was untenable. Also the rear bearing oil filler is missing. If your FIL has a chance to inspect, look for abrasive dust residue. The pulleys have a kind of gray, dusty look to them. The seller doesn't show the parts of the ways you really want to see, and if the ways were flame hardened there ought to be a big "Flame Hardened" tag right above the SB casting, just like in the picture of the all-together one. Not all hardened beds had this tag, but it bears touching the end of the bed with a file. All in all, the market may be right, it may not be "worth" $200. If it were 20 miles from me, I'd probably have it in my garage right now, and be thinking, "Well, Jack, you've really done it this time."