Hasselblad Back question (answered)

I have two a12 backs for my Hasselblad. I am going to shoot test rolls tomorrow and noticed that the windows for the backs are different. The window I am talking about is next to the locking key, is a curve and changes from red to white. On one back when loaded and wound to frame 1 there is just a small portion of red on this curve. I assume this is correct. On the other back half of the window is red on frame 1. Does this mean that spacing will be off?

No.

The indicator probably slipped in one back, or some bit is bend a bit more in one back than in the other.

This thing is not linked in any way to the transport and/or spacing mechanism.
It is operated by a spring loaded feeler that pushes against the bright metal bit that pushes against the roll of film on the feed side of the insert.
Operation of the film back is not affected by it in any way, so no worries about frame spacing.

It's use is very limited: you can only see whether the film is indeed moving from one spool to the other by seeing if the amount of red that shows changes. It will not tell you how much is still on the roll, nothing about frame spacing, or anything like that. For that, you need the frame counter.
So even though it is not hard to adjust (if you know how), and it doesn't take much time to do so, it's not worth the bother.

Thanks for the answer!

Here is a pic to go with my original question, just to clarify for those who might be wondering the same thing.