They can vary in look by mfg, but the pinouts of the different 12V types are the same, but they are not interchangeable.
You should be able to see the markings and see if your tubes are knock off of 12AX7. This is a rundown of 12AX7 variants and all their weird names:
http://www.audiotubes.com/12ax7.htmOther tube types are described on the parent page:
http://www.audiotubes.com/bjlinks.htmYou can find a lot of pictures of tubes on Ebay, no guarantee they are accurate though!!
The markings, if genuine is your best guide to what you have, not the pictures, because glass can vary but circuit inside is same. Glass and pins are identical on most of the 12 series. Markings can be wiped and repainted to make forgery because some of these tubes are worth $500^. But I assume you've used these before and know they are real.
If you have some strays that you don't know what they are, I know someone who can ID them for you by testing. Actually I bet Steve can do it with that awesome tube tester he has!!
Tell me if you see a bright flash!
haha
Rich