@Markeologist @T-Mar Gentlemen, again, thank you so much for this information. This has all been a huge help. So, looking at my bike (1962 or earlier) here is what I'm tracking for possible frame builders from what I've gathered from various sources;
Gitane (MICMO) - probable, frame characteristics seem to match so far (I will post more pictures of my frame when I get a chance)
Carre - No, seat stay cap construction doesn't match
Cizerone - No, serial number placement doesn't match plus Cizerone contract starts later (1966)
Lejeune - Unknown, but Lejeune frames may have been made by Carre at this time
Mercier - Unknown
Italian manufacturer - No, Italian made Geminianis are produced after Cizerone contract presumably ends (1970's??)

So, are their any defining characteristics that I should look for to confirm or deny Lejeune or Mercier manufacturing?
@Markeologist my bike is labeled "R. Geminiani Special" as opposed to the normal "Raphael Geminiani". Does you RG catalog mention this "special" model or say anything about it?
Again, any help would be greatly appreciated.