How Can I tell if the tubes I bought are vintage?

I am a tube novice. I recently bought a pair of used 'vintage'(1960's) Amperex Bugle Boy 6DJ8's (for my MF X-10D). Is there any way to determine if they are indeed older tubes versus new copies? Would someone be able to tell from looking at the inside of the tubes (these appear to be brand new inside the glass). The seller said they tested well below new levels which I figured was fine for my limited usage and budget. Please enlighten me. Thanks