I see listings for Mamiya 645 Pro backs which say "red tab" or "blue tab". That obviously refers to the color of the handle on the dark slides, but does that indicate anything else? Are they actually different models?
I've always wondered the same thing. The way that some people advertise them, it's like "For sale: back with <colour> tab, so much better than <othercolour> tab".
I did get a few red-tabs with my 645AF, and I see blue tabs more often on 645AFD /2/3 models. Maybe blue is just later?
Still, never had a problem with my Reds...