Right. Older cellular iPads supported either GSM or CDMA, so you had to choose at purchase in the US whether it was for AT&T (GSM) or Verizon (CDMA). Newer cellular iPads include both GSM and CDMA.
The best part about this: iPad boxes never said which carrier it was locked to. You had to look it up via serial number. Non-Apple sales people didn't seem to understand this and happily sold me an AT&T iPad when I asked for a Verizon iPad.
Yep, same here. I have a first gen iPad, a first gen retina display iPad, and a couple of iPad Air now and only the first gen didn't have the carrier on the box, but that's because the first gen was ATT only.