You see the 5 x 4.5" versions from time to time, but aren't the 5 X 4" versions as rare as hens teeth...? I like them personally - mainly because of their rarity I guess. Same reason I like those old Hurst wheels...
You guys are right about the B5 variation and all of the reasons for it. One of my '70 340 Dusters is B5 and it was done in Amerflint back in '89. I'm not sure I've ever seen another B5 that looks quite like that one... LOL!