Here's a shot of the etch. I know, it's blurry. Sorry about that. As you can see, no date code on the lamp. (???) Why's that? It was in that 12-Pack box.
Most older American lamps have the date code on the stem press instead of the etch. That's a nice oldie! That 12 pack does it state the hours and lumens? If so it is 70s, if not its 60s.