witch rearend is in the 2004 5,3L ext cab 4x4, automatic silverado .. is it the 8.5 30 spline ? looking to put in a eaton posi .. and is it 10 or 12 bolt ? and what size is the front differential

thanks

 

rear is a 8.5" 10bolt, i believe its a 30 spline?
the front is a 10bolt, not sure what exact size..