Also, you can refer to IrishPipes recruitment thread to see all schools with current NPC and dormant NPC groups. It's on the first few pages of her recruitment thread every year and she updates it.
Two things: gamma delta was my chapter and it was active from 1950-1989. Second, I saw that pin, too, and bought it! It is safe in the hands of an APhi and a gamma delta APhi to boot. I'm going to have my chapter guard attached and wear it as my pin.