I'm sure there is some miscommunication. Believe me, with those guys, it's not hard. They just drilled two 1 3/4" holes in my tank, so I'm sure they have the bit. That's the standard size for a 1" bulkhead. Go down there, talk to the guy (Mexican guy, speaks only a little english) who actually does the drilling, show him your bulkhead. He'll get it right. He's pretty sharp; it's just communication between him, the owner, and the phone is not always so good.

BTW, I've never seen a 1 1/4" bulkhead. If you have one, I'd like to see it.