lol, I was not trying to prove you wrong my gentle friend. I posted the short cryptic answer by mistake before completing it and could not edit it on tapatalk, so decided to wait till morning to complete my post.
OK yes you are correct there is NO production yellow gold 15400. 100% true.
I wanted to explain that what I saw once at a gathering in 2016, was a custom piece, which started as a 15400OR black dial, but it has been "converted" to a YG (plated or otherwise) piece, including the hands and dial markers too. I do not know if you could plate RG per se, but the bugger pulled off the project. So your post brought this watch to mind, and I just wanted to share it. My apologies for how my post appeared. To me, that was a genuine custom piece which appeared to be a full yellow gold watch and I remember what the owner said in general but not the details of what was done. That watch was not a rep as it had the gen caliber, proper caseback engravings, proper weight, gen hands and dial etc.
