Can you think of anything id need to ask about that hasn't been listed? I don't want to regret dropping $6750 before tax..
I always check for crank walk by trying to push the harmonic balancer in and out of the block. Any discernible play indicates wear to the #4 crank bearing. IIRC specs are 0.003-0.006".
My original engine had about 0.090" and ran fine, but I pulled it to refresh and install a good, used crank. I came upon another used engine with about 0.060" play and have been running it for over a year. I had pictures in my profile thread, but they aren't there now. PM me if you'd like more info.
I bring this to your attention to use as a possible bargaining chip with the seller. The engine isn't going to explode and I suspect a great number of M42s with high, city-driven miles are like that.