Rat Rod Mac,
There are several questions within you inquiry. The total value would be dependent on several factors. I'll try to be brief but there is a multitude of things that come into consideration. First, the case. IF it is genuine U.S. issue then it alone would be worth several hundred dollars by itself. However, there is a flood of reproductions on the market and only someone very familiar with the real ones could tell. If the canvas looks too new, kinda thin and the print is dark, then it is probably a reproduction. The folding stock is another issue. There are reproductions out there as well that sell for a little less than $200 but a real U. S. issue M1A1 stock may run you more than a couple of mortgage payments alone. With the reproduction stock, the wood is generally ok, but it is the fit and finish of the metal hardware where the problems show up. The locking lugs are loose, some manufacturers use fake leather check pieces and the rivets are not right. The value of the rest of the weapon would be subject to exactly what parts are on it. The original carbines as they left the factories underwent several modifications toward the end of the war. After the war all carbines in the U.S. inventory went through depot rebuilds. Most every carbine received the latest modifications. The rifles were stripped down and parts were just put in bins then reassembled without any regard as to manufacturer. So there were no rifles in an original "as left the factory" condition. Collectors spend a large amount of time and money researching and looking for the right parts to make their rifles "correct" for the period of manufacture. There are some that are still in original condition that were brought back by returning vets. So if someone says that they have a documented genuine vet bring back, they are also saying they are in possession of stolen U.S. property! Check out surplusrifleforum.com. There is a dedicated forum for carbines and the folks there are a wealth of information on about every facet of the M-1 Carbine.
Post war rebuilds will have: adjustable rear sight, round bolt, rotary safety, Type III barrel band (the one with the bayonet lug). Early to mid war carbines will have: flip rear sight, flat bolt, push button safety, Type I or II barrel band (no bayonet lug). Some upgrades were installed in the field as parts became available before the end of the war. If they are in the "correct" condition the early production carbines seem to bring more from collectors. Then there are more desireable manufacturers based on numbers of production.
Only someone very knowledgeable on carbines after inspecting your rifle could give a realistic value. However, should the case be genuine and the stock U.S issue and the serial number in the M1A1 production range and it is as it was issued, then you could easily be looking at anywhere between 2-4 thousand or more. If the case and stock are reproductions and the rest of the weapon is in good condition (no worn out parts, good barrel, etc) then it may fall in the $800-1100 range. Carbine prices are going up every day as they are becoming very popular again. I have a 1-44 Inland in real nice condition I bought in the mid 80's for $250. I probably could sell it today for $900-1000 easy. I hope this has helped but it is just not possible to assign a value without a detailed inspection.
