The barrel is not ramped, it's just a regular 1911 barrel but 7 inches. IT's polished, both on the barrel and on the frame. Mine eats 200 grain LSWC beautifully.
I don't know if you could use a FLGR with it... you'd have to find someone that used a FLGR on a long slide and get their parts. IMO, I wouldn't bother, since most 1911's can be made to run just fine without one. It uses a standard length recoil spring and I use a regular old Wilson Combat 18 pound spring in mine. The recoil spring plug is a non-standard item, because it looks and works like your basic recoil spring plug, but there is an extra two inches of solid metal... it adds a little weight to the front end and fills up the space between the end of the spring and the barrel bushing.
The frame is basically standard 1911, but with some "issues." I haven't hand any 'smithing done on mine and I don't have the skills to do any myself, but in the reading and searching I've done, dimensions can be a little sketchy. Either the dimensions are basically there and are erratic across the entire production run (most likely), or the dimensions are off in some key places, so the basic items would likely be fine, but the internals might be a bit more work. The problem that most folks had back in the day was that most quality gun smiths didn't want to work on an inferior gun. The only place I can be more specific than that is with the ejector... unlike a standard 1911, this one is not pinned in place, it's welded, so to start from scratch it needs to be dremeled off and a new one held in place... somehow?
When I got mine (used) in '88, it wasn't the tightest slide to frame fit in the world, but it wasn't awful. The fit and feel is exacerbated somewhat by the fact that it is two inches longer, so it's even easier to see/feel any play in the fit. It wasn't incredibly accurate and the barrel bushing fit quite loose in the slide, so I replaced it with a Kart bushing that's fit so tight that it's nearly impossible to install/remove without a bushing wrench. And the bushing to barrel fit on this Kart piece is INCREDIBLE and it makes the gun run beautifully. It's accurate, it's reliable and it's a joy to shoot. I feed it lead semi-wadcutters pushed by 4.4 grains of Bullseye most often.
When this gun came out, it was one of the first (if not THE first) all stainless 1911 offered, and that was groundbreaking for the time. There have been many reports of galling between the slide and frame, but mine hasn't suffered that fate. It should be run at least a little wet. For the money I paid for this one in '88, I've been BLOWN AWAY by how good it's been to me. And if it cracks or falls apart the next time I shoot it, I wouldn't be able to complain. (I shoot this one as much as any center fire handgun in my safe)
For your needs, if you were somehow able to find one discounted that had a problem, I see no reason why you couldn't put the slide on a standard 1911 frame built by anyone. The barrel too, but as I said, Storm Lake will build a new one in 7 inches. As far as I can tell, the slide takes all the usual firing pin, extractor, parts etc. But you could also find a whole one used and try it out just as it is and go from there.