As long as you like the sound, that's what matters. I think as long as you use the proper care with your cymbals it should be fine. A crack would be another story. But I've had a few rides and crashes with key holing. Actually loved the way those cymbals sounded.

I sometimes wonder whether the keyhole is the sign of a much played and loved cymbal. Or it could just be neglected. Keyholes don't bother me and I don't think they affect the sound. Generally they will be cheaper to buy, too

I buy vintage Zildjians all the time with keyhole issues. It doesn't bother me if the cymbals sounds good. When it comes to resale,maybe a different story. Hairline cracks around the center hole is what I look for.

Buy it, don't worry about it. Offer $100 because of key-holing, then buy a grombal:

http://www.thegrombal.com/gb_info.htm

I use these. One of my cymbals has extensive spidering from the center hole, it has not expanded since I put on a grombal.

If the key hole width is less than the diameter of the sacrificial nylon tube that is usually covering the threads wing nut threads at the top of the stand or cymbal arm, you should be OK. If it is really large though, it could cause the cymbal to get hung up and choke.

The key hole is the result of not having that sacrificial piece in place and allowing the threads to slowly break away tiny pieces of the weaker cymbal metals.

Thanks for the confidence guys, hopefully I'll report back soon with a good score.

So I revisited the pawn shop with my glasses this time LOL. The cymbal is a '68-'70 Zilco non-hammered turned cymbal from Canada. I also had the price wrong, they want $99 for it. Still thinking about it, I still like the dark sound it has. Maybe I walk back in there with an old Fostex four track I have laying around and $50.

Bring in a ride you are familiar to a/b the cymbal.

If the price is right, I wouldn't overly worry about keyholing. It will affect the resale.