Gears & Axles - *Help* 2 or 3 series *pics*

ok so im not sure exactly what rear is in the car... previous owner said he bought the 10bolt and couldn't remember what year car it came out of but said it was a 4 channel 3 series rear... The rear has Richmond 3.73S and a Auburn carrier... i broke a tooth off the pinion so i was going to throw a new ring and pinion in it. Problem is i went to summit and ordered a 3 series motive 3.73s(part#g875373) and the motive ring is alot thinner(see pics) so my question is do i have a 2 series and need a 2 series ring and pinion? (sorry for the noob question but rear ends aint my specialty)
motive(thinner) vs richmond
http://farm8.staticflickr.com/7254/7546663008_b367d4c483.jpg
http://farm8.staticflickr.com/7279/7546716446_9d4bdfe101.jpg
http://farm8.staticflickr.com/7128/7546718086_df84f0c8d5.jpg

the carrier looks to be a 2 series

http://i258.photobucket.com/albums/hh254/oldmanZ28/rearend%20technical%20pics/DSCN4539CAwvaluesAwTS.jpg

Thank you i appreciate the help, looks like ill be heading back to summit.

That's a 2 series. Fat ass ring gear is a dead give-away.

I wanna know if these are for a 2 or 3 series carrier! Help!

What ratio(teeth on pinion vs teeth on ring gear) are they,what are the part numbers on ring gear,and a side pic of the ring gear helps in identifying.