I think you're about right with 92/93.......I had a 95/96 IBOC CompSX which was the bonded aluminium frame and yours defo appears to be earlier than that, I can't help more than that I'm afraid!
Notable differences are the top tube cable routing (side vs top) and the rear brake cable stop on your bike versus the seat tube noodle on the '95. And here's my 1992 Pro SX also with bonded Carbon fibre/aluminium frame: http://www.retrobike.co.uk/forum/viewtopic.php?t=13577&highlight=mongoose
I bought mine new in 1992 and that has a canti stop mounted on the monostay seatstay like yours.
Here is mine. group is mostly original, and i'm sure its a '92 from the rounded sti levers. the 1990 (brochure somewhere on here) has splatter paint, mine and yours do not.