Reading some of the comments here... let me see if I can ease your mind some. The first automated Strat pickup winding machines were introduced between 1965-66 and both Fender and Gibson began using them by 1967. Even then, they still employed workers to hand wind special pickups (pups) and still do hand wound pups today. As a marketing device, Fender didn't begin advertizing hand-wound custom pups until their 25th anniversary model in 1979. Years earlier, the buzz on the streets was that Jeff Beck, Eric Clapton, Richie Blackmore and other famous guitarists were trying to get a hold of the pre-CBS Fenders Strats because they believed the pre-CBS pups were more consistent and distinctive for hard rock. So 1979 CBS started actually marketing their custom Strats as "hand wound" and many were actually outsourced and mass produced by DeMarzio for Fender. CBS Fender introduced their Elite Strat in 1983 with hand-wound custom pups.

So the hand-wound pup marketing campaign really took off big in the mid 80s, even though they were around since the beginning - just never advertized much until the 80s. In fact, the last big marketing push was from 2010 to 2013 with the "Abby" Abigale Ybarra hand-wounds. She worked at Fender from the beginning in the 50s and wound pups for many famous guitarists. She has retired, but her pups can still be found on used custom shop models.

So as you can see, saying "hand wound" could mean any number of guitars from different eras. Without something like a purchase receipt that might include the serial number, it would be impossible to locate it and there's no other certain way of verifying it was a rare CBS model. So don't beat yourself up too much. The Fender Strat has been through so many changes, upgrades and reissues, hell even us Strat lovers have trouble keeping it all straight. Just speculation, but it could have been a Japanese model that he had someone upgrade the pups to the hand-wounds. There are so many possibilities. There's no way you could have known its value without knowing some background on it. Besides, I'd like to think that a respectable guitarist or collector would not buy it out from under you without letting you know you have a rare model. Yes, some people have no shame, but I know I'd never fleece someone and take advantage of their lack of knowledge. I'd have to make a fair offer, and most people in the business feel the same way. So, don't kick yourself. Now you have a greater appreciation from the experience.