1971/1972 10-Bolt Rear Axles

Hi.

Do all 1971 Oldsmobile rear axles have cone-type positraction units? We have
a '71 rear axle supposedly from my brother's '71 442 that has a clutch-type
positraction, with "C" clips. It has the 10-bolt axle cover with the brow from
the 12:00 to 3:00 position. It is a 3.42 posi unit, but the code on the
passenger side tube cannot be located.

How do you tell the difference between the '71 10-bolt carriers, being those
that carry 3.42 and higher (numerically) gears, and those with 3.23 and lower
gears? Also, how would you differentiate the same with 12-bolt carriers?

Thanks,
Anthony