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
There are several websites that address this subject, just search for NOS TUBES. The tube vendors usually have a section that talks about that. I got my tubes from Kevin Deal at Upscale audio, who is a member. Very good results.
Did you try just asking them nicely?

If they sound good, don't worry about it.
post a pic if you want anyone to pass judgement on these.
Tim, thanks for your insightful advice.
Sugarbrie, you are right. I have not tried the tubes yet but am going on the assumption that authentic tubes will sound better.
Ed, good idea. The tubes can be seen at :