A lot of the 1st gen Glocks were issued to Law Enforcement Agencies and were up-graded with new trigger bars, fps, firing pins and extractors. They were used and abused by the Police and eventually ended up on the Surplus Markets, which have long since dried up.
I go to gun shows all the time and when I do see a 1st gen they are almost always in fair condition. A few years ago I found a NIB AA*** Glock 17 for selling for $400. Some old man had it, and I would have bought it but at the time I didn't have any money with me. A like new minty Glock 17 gen 1 can sometimes be found on Gunbroker.com
I happen to own a minty gen 1 that has all it's original components. It has the black serial number plate, all the black guts and does not have the lanyard hole in the grip. I baby this gun and occasionally will take it out of the safe and shoot it at the range.