Russell,
Bill went home with 902's from Bill H/Great Plains. These are new units other than me using them as I am the original purchaser. So these(even though they say 902T on the back are 902B's.Bill had no 902B decals, so I said better to have a wrong one for looks than none at all.
The only reason Bill went home with them is because I have a pair of used 902B's with "push-terminals" and Bill sends them with industrial spade lugs that I can't use as I am always swapping out horns and drivers like most folks change underwear.
The 806 is a smaller magnet version of the 802(both having aluminum diaphrams). Putting a symbiotik diaphram in a 802 becomes a 808, and the same in a 806 becomes a 807. Better power handling, poor HF top end response. There is always a compromise somewhere. All 4 of these models are alnico. The 902 is a ferrite magnet/tangerine phase plug.
I just did a unofficial shoot-out with a JBL 2426 and found the 902 superior(to my ears). The 2426 is higher output in the upper midrange, the 902 is better on the upper HF area.
Ron