Correct buckle for 1969 Genève?

I have a 1969 Genève (166.070, 563 caliber) but when I first got it it had a Spiedel metal stretch band mounted, so I've never had an original strap or buckle.

I'd like to get my hands on a period-correct buckle, but I can't figure out whether that should be the "older" style:



or the "modern" (1970s) style:



From what I gather the transition was right around the turn of the decade and wasn't instantaneous. Does that mean I could use either? I prefer the look of the older buckle on its own, but I recognize that the angles of the newer one might match the design of the watch a bit better. Is there a correct answer?

Thanks!

The answer would likely be predicated on "what country did you buy it in?" I wouldn't be surprised to see either of those, or indeed, this:

Ah, good refinement. The watch would almost surely have been bought in the US.