Sorry to go slightly OT, but doesn't the term "4130" include the cro-moly tubing from all of those makers? For a while, I thought it described something lesser, but my reading since then has led me to believe that steels like Columbus SLX and Reynolds 853 are properly described generically as "4130."

Back on topic: That "bashguard" on the crankset and the fact that a knowledgeable seller doesn't mention the grade of steel would suggest to me that the "gaspipe" assumption is correct. What gives me pause is that the geometry looks a little tight for most hi-ten bikes from the 80's. Why don't you email the guy as he reqeusted?