Given the seller's good feedback, I suspect you'll be fine. I too have bought lots of old tubes with no real issues.
Old signal tubes rule.
Old signal tubes rule.
Used tubes question
I bought a used quad of xf2's. They were cheap, 150.00 bucks, so I figured I'd give this older-mullard-tube-thing one reads about so much a listen. Now I worry about putting them in my intergrated. I have a Leben CS-600 and fear it going up in flames. The seller said they were closely matched and tested on his such and such tester. He had plenty of positive feedback. Should I just pop 'em in and see what happens? What is the worst that can happen?