Jeff,
The "BE" axle code is COPO 9560 and COPO 9561 specific. It was generated for those option packages.
The "BE" will only appear in box #258 on the broadcast (build) sheet. I will not appear on an order sheet or window sticker, beacuase it is part of the option package.
The internal HD parts were OTC in 1967, but not the complete axle assembly.
The only warranty service rear I have seen in a COPO had a blank tube and OTC internals.
Hope this info helps,
Eric