^^^^ he said 'prolly' ^^^^
In all seriousness, two ways to tell about the rear gear, first look at the rear end cover, there should be a tag on one of the bolts, clean it off and write down the characters (numbers/letters) there are places to go to de code it, if no tag it likely has been changed, go to the door tag and there is an axle code there. This tells you factory installed ratio. You can pull the cover and look for numbers on the ring gear. Or:
Now you are going to need a friend, pick one that can count or has at least 8 fingers and 2 thumbs.
with the rear end jacked up and on jack stands (do not use harbor freight jack stands, there is a recall on certain ones) mark the drive shaft, I would start with the tire stem at the top or bottom, turn the wheel/tire slowly, the drive shaft is going to turn 2 or 3 times faster, 10 revolutions counting the drive shaft revolutions, you can turn the wheel/tire one time but it will be an appropriate, best guess, 10 times is more accurate. It will not be exact but will get you in the ball park.
Example:
30 drive shaft turns = 3.08
37 =3.73
I do it twice just to compare counts.