Thanks! It's 231.13.42.21.02.002, which I believe was only sold on strap. Sharing this compilation I had made to track these particular variants. There were also the 38mm models but I didn't track those.
Incidentally, the silver/all SS and the RG bits variant have slightly different color dials. RG bits being more off-white, which I thinks looks very nice. Terrible pictures, but you can sort of make that out in these side-by-sides I took years ago when I had both.