If its been maintained, then the #14 head as said previously is a non-issue. For that matter, a #17 and higher head doesn't mean much if the car has been beaten up.

I have the original #14 head on my SDL - the short block is a MB crate with approx 150k miles, while the actual #14 head has almost 270k miles. The only reason the short block was replaced is when the P.O. cracked the pan at highway speed. The car is still a pleasure to drive, and we frequently take her on long road trips up/down the CA coast without any hesitation.

For piece of mind, you might consider getting a pre-purchase inspection though.