I just bought a set of b Body axles and they have a set of the sealed "Green Bearings" (non adjustable) on them. They seem to have some resistance to them when trying to turn them. Is this normal?

I don't know much about the axles or their history and I haven't owned any axles with green bearings before.

If they are new, they turn just a little stiff. If used, they should be a bit easy to spin.

They are a ball bearing type bearing, not a tapered Timken tapered roller bearing like the stock types are.
I would wrap my hand around the outer race and rotate the race against the bearings for several revolutions and see if you can feel any rough or tight spots If so replace them

I do believe those are sealed bearings. If so, what you are feeling is the rubber seal. As stated, after some run time they get looser.

Usually the green bearings pull the axles in closer to the housing and the axle ends run out of end play, so you may have to grind a small amount off the end of the axle so they don't but up solid .