Which Posi?

[blueranger]

My 2000 Firebird has the 3.8.
4L60E trans
The RPO codes for the rear end are G80 and GU6, so I have a posi with 3.42 gears.
I'm not sure what rear end I have. Do I need to get under the car and look/measure the rear end?
Would anyone know what I would ask for in a new ring and pinion?

Edit:
I'm thinking this is what I need to know?

3 series carriers 3.23 & Higher

* 8-5/16 x 10-9/16
* 10 holes
* oval
* Ring gear diameter 7.50
* 10 3/8 x 18 lh Threaded bolts
* Pinion Diameter 1.438" 27 splines

[A fireman]

Re: Which Posi?

ring gear on a 3.42 is 7.65"
but it looks like everything else it right