[TA Forbes]

Doug, I think we are saying the same thing. The insert underneath the glass has different size windows for the different number of bands present on the dial scale. The size of the bezel ring can be, but not as much. My 38-665 and my 38-5 both have the same size bezel ring, but the 38-5 is a 2 band and the 38-665 is a 4 band. My 38-2650 is also a 4 band radio, but it has a larger bezel ring.

In my opinion the actual diameter of the bezel may be due to cosmetics or designer preference in addition to the number of bands.