Vintage Longines: stainless steel back and solid gold superior case

Hi,
some of the vintage brands did (in the 40s and 50s) a strange thing for today (from my knowledge).
They made watches with stainless steel back cases and 14k or 18k superior cases (the upper part).
This was the case (from my exerience, until today) for Certina, Alpina and Omega.
I owned many Certina with this feature, 2 Alpina and never an Omega (but a friend had).
This is the reason why, when i saw on ebay a Longines 9l with a case back written "acier inoxydable" - and not "Fond Acier Inoxydable" - and a rose superior case (advertised as gold filled (?)) i had to buy it.
It arrived today and... it really is a rose gold upper case 😀
Have you saw or have in your posession another Longines with a stainless steel back and a gold (full, solid gold) second part of the case?
Because i am lazy, i will just add (for now) the pictures from the ebay ad.
P.s.: yes, it is a redial.

i can speak only for the ones i had: they were not marked 😀 Certina, Alpina and now this Longines.
Certina had a special reference that linked the case reference number with steel backcase & gold superior part, but that was it.
For Longines... you just know (the closest jeweler is your friend 😉 )

i
this one has a 23.0 or 23m movement inside?