identifying rear-end gear

i have an 8 1/4 rear end in my car, that, as far as i know, is completely stock. i was hanging my muffler the other day and looked at it, and spotted a tiny tag on the right side (if youre looking from the inspection plate side) that read "2.45" and that was it. it was bolted down with one of the plate covers.
would that be the gear ratio in it? there was another one with some numbers on it, but i couldnt make heads or tails of what it might be.
if thats NOT the ratio, then how can i find out ?