I’ve just started collection about a year ago. The folks here on this forum have be a great help to me. If you have questions on a specific lock,. please post a picture taken next to a ruler or other way to a good context for size.
As to “fair market value” - that is a very tough one with no simple answer. I’ve been buying locks/keys on ebay and what I can tell is that the price many lock sell for changes as fast as the wind. You’ll maximize the value if you can take a long time liquidating them - observing first the ‘going price’ and then hold a bit. If you have to sell all at once, you’ll not be able to sell each lock to the most “motivated buyer”.