Confused about my Conn!

Hey guys! Completely new here, and this place seemed like the best place to come for information and sax loving people.

I was just given a Conn from my grandmother, and this thing looks brand new. She bought it for her son who passed away, so he hardly played it and it remained in it's case since then.

I've done as much hunting as I possibly could and came up with a lot of pretty solid information but I'm still confused about the serial number. It's H21337. Like I said, it's a pretty much brand new sax so I'm 1000% positive it's correct. The serial number lists I've read says numbers with "H" as a prefix start at 31247. Is my sax a "mexiconn"?

Thanks in advance!