Ithaca, Singer Sewing Machine, Remington Rand, Union Switch and Signal all made .45 autos during the wars. They are all pretty valuable now. I don't know which brand would command the highest price, but I'll bet your $35 investment is worth at least a grand now. Condition is everything, and I'll bet yours is still in excellent condition. Still in cosmoline the price would about triple. Very rare. A nice find for you.
I got a Remington .45 auto back in the late 60's as part of an estate sale, along with a couple Walther PP's.
I mildly accurized the .45: I installed Micro adjustable sights, Micro barrel bushing, lapped it in, shaped and polished the feed ramp, enlarged the ejection port, tightened the slide, added a heavier recoil spring, changed the trigger and a couple of other things that slipped my CRS mind. I later gave it to good friend and he still shoots it. :)