Picked up an O/O27 Supermarket that's shallower (or skinnier, the side walls are shorter) and has a centered door with windows on each side on Sunday. Is it the original version of this building? It has a BB logo on the back wall. It's missing one side wall, too, but I wonder if the HO gas station can provide the replacement.. I'll have to dig one up and see.
At the same time I picked up a couple of the O version that are just like the HO one with the door on the right and the add on sign piece with the overhang. (mostly because I didn't realize the first one was missing that, so I got one that does have it). They have longer side walls with two molded in windows.
I also got a Plasticville Bank. Thought maybe it was OOP, don't remember seeing another one, but I see you can get it built up as I look on eBay. I got it because it looks pretty good, I've seen quite a few older bank buildings that it resembles pretty well.