I'm wanting to pull the axles and replace the bearings and oil seals. I'm using a Haynes Repair Manual. It give two different ways to doing it. One way it tells ypou how unless your rearend is an O or an E . Then it tells you how to do it if it is a O or E. How can I tell which rearend I have?

Sure that's not a C for the E ?
You should have a C type if it's the original rear.
Post the casting number -on the back ,near the bottom of the center section.

The Chevy rear ends haev c clips that hold the axles in. The others have press on axle bearings with bearing retainers bolted to the housing ends. If your rear end cover is round with no cut out areas at the 3 and 9 o'clock positions then you have the Chevy rear end (unless it's the O rear end). If it has a cut out at the 3 and 9 o'clock positions then you have bolt in axles. The O rear end has 12 bolts in the cover, but the cover is smooth without the upside down V stamped into it.