I mean, the stock set up is 3.07 gearing with an open differential yeah?
If you need confirmation then open it up!
seeing as you want a new rear, I'd only open the front,
as the old rear gearing doesn't really matter, as it's going to be replaced.
when you crack it open it'll look like this-
this is a 35, the rear, with 4.10 gearing.
so on yours spin the ring gear until you can see the last numbers (mine is 37/9)
divide (36 goes into nine four times with 1/9 remaining, which is 4.1 with a repeating decimal, the closest ratio to that is 4.10)
should be 3.07
then look at your differential,
if it looks like this:
if not, then describe or take a picture, then we can tell you what it is, if you don't recognize it.