which carrier unit is in this car?

[RARON455]

Little help here fellas, I have a 98 trans am, M6 I the only mod I have is the volant cold air intake and smooth bellows. The only mods I would ever plan in the future would be an ls6 intake and possibly headers. I have heard of the weaknesses of these 7.5 rear ends, I have a 3.42 in mine, and it has too much backlash for me, so I was considering swapping in a set of 4.10s and putting a girdle on it. I would like to get a 9 inch but spending 2k is not an option. So I am stuck taking my chances with the 7.5. I do not take it to the track, I have another car for that. My question is
WHAT CARRIER DO I HAVE? I have seen statements such as series 1 and series 3 I am confused as to which on do I have? thanks

[2001NBMZ28]

3 series for the LS1 A4 (3.23) and M6 (3.42) cars. A4 LS1 (2.73) got the 2 series. If I'm not mistaken '98 was the last year for the standard Auburn, '99 and up got the Torsen. There's also 3 or 4 channel ABS depending if the car has traction control or not.