I've seen several Blaupunkt radio pictures. I notice that some start at FM 88 an others start at 89. Can someone educate me on the difference or year applicability? Thanks.

None that I know of. Radio shown is a later model because of the black face and square corner. Should be a 74-later model

Well crap. The corners appear to be a subtle but interesting distinction if you are going for originality. I completely overlooked it, but it seems to coincide with the 88 vs 89 FM marking.

Perhaps another distinction is the chrome surround. Is that part of the main radio body, or is that the removable faceplate?

I just pulled this radio from what I think is a 1974 914, and I was hoping it would be a Frankfurt that was correct for our 1970 914-6. No such luck I guess.

It appears I'm looking for this one, sans the faceplate (photo credit dr914@autoatlanta.com) from this related thread.

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Perhaps of interest: I noticed today that the square corner part comes off as a separate bezel. The radio underneath actually has rounded corners. I wonder if a simple bezel swap, assuming you could find one, would make all the difference.
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Face swap should be no problem