Supershaft, when I originally pulled the heads, I was surprised the chambers were so clean. I thought that perhaps the PO actually had done some maintenance. The first valve I pulled, however, looked like this so I assumed they were all the same - actually the rest of the valves look pretty good. You're right, evidence now points to a 'recent' valve job.
I've read the cam sprocket doesn't wear as quickly as the crank sprocket so based on your comment, I compared the old cam sprocket to the new crank sprocket. Looks acceptable - would you agree?
Good tip concerning removal of the seal - I think I'll take your advice - thank you.
Disston, as I mentioned in my preamble, this bike is like a time capsule. You're probably seeing parts you haven't seen in years.