Most brands of LED watch don't have very high monetary value today. The exceptions are the rare models of name brands such as Pulsar, Hamilton, Omega, and Synchronar. For an LED watch, if it works that's half the battle, but the cosmetic condition of the case is probably just as important to monetary value. Still, if it's not a big name it probably won't be worth a great amount. If it has an unusual or rare style it will be worth more than the run of the mill.
Most poeple who collect LED watches do so not really because of the money, but because they feel that the technology was unique and cool and too short-lived.
If you have a working vintage LED watch that you like and is cool looking that's what the hobby is all about. If you want a large amount of money for it, you'll probably be dissapointed.
There isn't a lot known about the majority of companies that made LED watches in the 70's. Most historical information is available on the pioneering companies mentioned above, but even there there's lot's of missing information. The LED 'era' was very short: 5, 6, 7 years at most. During that time many, many, companies produced LED watches, though the electonics inside them were made by a few well known companies. Most 'LED watch companies' were just buying cases and modules, putting them together, stamping their name on them, and selling them. So there isn't much going on 'behind the scenes' in these companies to research.
Though the LED era itself was short-lived, it is really still going on today in the form of all modern digital watches, because LED is where they all came from. Enjoy your watch.