Anyway .. after I figured out how to pry it open.
Its a Sentrol 5728T, "MFG 9649" (I'm guessing that means it was made in late 1996).
Combination acosutic glass break and magnetic contact switch.
There were 4 wires, 2 for the glass break and 2 for the contact.
Can't find a lot of info on it, but considering its actual age and that its 20 year old tech ... it goes into the trash.