Genève Megaquartz 32 kHz ref. 196.0030 - plain exterior caseback?

Hello everyone,

I’m hoping members familiar with the Genève Megaquartz 32 kHz can help identify the caseback on my gold-plated ref. 196.0030, fitted with caliber 1310.

The exterior stainless-steel caseback is completely plain, without an Omega medallion. Inside, it is stamped 1960030 and carries the markings specifying a 20-micron gold-plated case/bezel and stainless-steel back.

I’ve seen examples of this reference with a prominent Omega medallion on the back, so I’m curious about the difference. Is a plain exterior a documented factory variation, a possible Omega service replacement, or more likely an original back that has been refinished?

Are there particular markings, machining details, or finishing characteristics that would help distinguish these possibilities? Comparisons with documented examples would be especially appreciated.

Thanks for any insight,
Marcus