Welcome. Glad to hear you are doing alot of reading. Best thing you can do is read and learn.
The gold markings on the RG case are correct, but these same markings are also on the stainless cases (the TD dont show pictures of that though). The deployant buckle and the inner bezel both say stainless steel, even though it is gold colored....the factories do this for ease of manufacturing and lower costs. It is a common practice and has been seen on many watches through the years.....we get used to seeing these minor flaws....and you will to.
Factories make 1 case and 1 deployant for a watch model. The good news is that since you are getting the gold case, you have the correct markings on the case and all the buyers of the stainless case versions have the incorrect markings.....but the tradeoff is the deployant says stainless....but no one sees it as it is always closed when its on your wrist.
I also purchased the ZF RG/White dial Portuguese...I owned the GEN version of this watch years ago and it was one of my all time favorites. Elegant and classic IWC design. Cant wait to see my QC Pics.
I don't have the hall marks on my st/st version and haven't seen others with it. I hope they put a hall mark on the white gold ardoise version, that would be a bit plus.