Sea Dweller 16660 Caseback Question

[gman5515]

Hello Rolex Forum,

I've recently come across a 16660 that I'm interested in. I've asked for some photos, and I'm a little curious about the inner caseback. The engravings seem odd to me, and there's a thick engraving line below the words "Switzerland". Any cause for concern?

Appreciate your kind inputs and advice on this. For reference, this is found on a mk 1 matte 16660 dial, with a 3035 movement, circa 1983 serial 8.05 million

Thanks in advance!