How To Identify Old-School Gamers

Knows that Chainmail is a game system as well as armor and probably knows where to find a copy if they don't already have one
Carries a stylish Dice Bag of Holding
First exposure to Steve Jackson Games was Melee or one of its later versions, including GURPS
Never throws dice away--gives retired ones an honorable burial instead
Seriously thinks there's no real difference in protection between a large shield and head-to-toe hardened leather armor
Knows CoC as "Call of Cthulhu"*
Has at least one full bookshelf of gaming books and knows where to find the little rules wrinkles in every one of them
Even when roleplaying well, can take any game mechanics and make a hideously overpowered character that's the same level as yours
Surprised by HR setting up roleplaying scenarios at work because roleplaying is about games

If you can think of any others that are not too obscure, feel free to write some in the comments. *This is the one that got me started on the list.