When installing the 3 O-rings on a Bravo lower unit (oil ,water, shift I think ,orange o-ring) Should you use Bellows adhesive on both sides before mating lower to upper?

No. You glue the O-rings to the drive only. The compression of the rings against the bellhousing is what makes the seal.

Thanks for that.. The drive meaning the lower section right?

Oops! didn't read your question as closely as I should have. I thought you were speaking of the O-rings that adhere to the upper portion of the drive between the drive and bellhousing that seal the shift linkage, gear lube feed, water inlet, etc.

I heard you just grease these up and install.. Hope the marina is right.