I have an 80s vintage I gave 180 for, shoots fantastic, great carry. I bought it about 6 years ago, so I'm thinking in todays dollars upwards of 225 to 250 would probably be a deal, no more and that would be in low wear. Mine has a lot of holster wear, but not much end shake or looseness.
I have an early 90s, pre MIM, pre lock, but newer transfer bar trigger system. It has a better DA and SA trigger than the older hammer block trigger 66 which is my 80s model. I think early 90s are the best ones from personal experience, but I wouldn't turn down the 80s model for a reasonable price. Mine's a tack driver.