If you wanted to have one of every different R9 variant this is what you would have to have:
Pre R SN, Early light grey anodized frame, Farmingdale, No sights marked R9, Blue CF grips (Ex. #127)
Pre R SN, Early light grey anodized frame, Farmingdale, Sights marked R9s, Blue CF grips (Ex. #128)
Pre R SN, Silver frame, Farmingdale, No sights marked R9, Blue CF grips (I don’t know if this exists)
Pre R SN, Silver frame, Farmingdale, Sights marked R9s (Ex. #321, #223)
R SN, Grey anodized frame, Farmingdale, No sights marked R9, Blue CF grips
R SN, Grey anodized frame, Farmingdale, Sights marked R9s, Blue CF grips
R SN, Grey anodized frame, Farmingdale, Sights marked R9, Blue CF grips
R SN, Silver frame, Farmingdale, No sights marked R9, Blue CF grips (I don’t know if this exists)
R SN, Silver frame, Farmingdale, Sights marked R9s, Blue CF grips (Ex. R343)
R SN, Silver frame, Farmingdale, Sights marked R9, Blue CF grips – (Ex. R600)
R SN, Grey anodized frame, Farmingdale, No sights marked R9, Black CF grips
R SN, Grey anodized frame, Farmingdale, Sights marked R9, Black CF grips
R SN, Grey anodized frame, Deer Park (Old English Text), No sights marked R9, Black CF grips
R SN, Grey anodized frame, Deer Park (Old English Text), Sights marked R9, Black CF grips
R SN, Stealth, Deer Park (Old English Text), No sights marked R9, Black CF grips
R SN, Stealth, Deer Park (Old English Text), Sights marked R9, Black CF grips
R SN, Grey anodized frame, Deer Park (Old English Text), No sights marked R9, Black G10 grips
R SN, Grey anodized frame, Deer Park (Old English Text), Sights marked R9, Black G10 grips
R SN, Stealth, Deer Park (Old English Text), No sights marked R9, Black G10 grips
R SN, Stealth, Deer Park (Old English Text), Sights marked R9, Black G10 grips
R SN, Black anodized frame, Deer Park (Current Text), No sights marked R9, Black G10 grips
R SN, Black anodized frame, Deer Park (Current Text), Sights marked R9, Black G10 grips
R SN, Stealth, Deer Park (Current Text), No sights marked R9, Black G10 grips
R SN, Stealth, Deer Park (Current Text), Sights marked R9, Black G10 grips
R SN, Stealth Elite, Deer Park (Current Text), No sights marked R9, Black Checkered G10 grips
R SN, Stealth Elite, Deer Park (Current Text), Sights marked R9, Black Checkered G10 grips
R SN, Stealth Elite Premium, Deer Park (Current Text), No sights marked R9, Black CF grips
R SN, Stealth Elite Premium, Deer Park (Current Text), Sights marked R9, Black CF grips
R SN, Special Forces, Deer Park (Current Text), No sights marked R9, Black Checkered G10 grips
R SN, Special Forces, Deer Park (Current Text), Sights marked R9, Black Checkered G10 grips
R SN, Robar, Deer Park (Current Text), No sights marked R9, Black Checkered G10 grips
R SN, Robar, Deer Park (Current Text), Sights marked R9, Black Checkered G10 grips
R SN, Custom, Deer Park (Current Text), No sights marked R9, Black Checkered VZ G10 grips
R SN, Custom, Deer Park (Current Text), Sights marked R9, Black Checkered VZ G10 grips
R SN, Tribute – Silver Frame, Deer Park (Current Text), No sights marked R9, Blue VZ CF grips
R SN, Tribute – Silver Frame, Deer Park (Current Text), Sights marked R9, Blue VZ CF grips
R SN, Tribute – Silver Frame, Deer Park (Current Text), Sights marked R9, Blue VZ CF grips with Crest
R SN, Mission, Deer Park (Current Text), No sights marked R9, VZ G10 grips
R SN, Mission, Deer Park (Current Text), Sights marked R9, VZ G10 grips
There were also the engraved models which appear to have been available with either silver or grey frames and had three levels of engraving: standard, medium, and deluxe, presumably with and without sights. All the ones I have seen pictures of had Blue CF grips. I doubt they made all of the possible combinations but that would add another 12 different models.
There was also R5000 the NRA special edition gun.
There was also a “one of a kind” auctioned here on the forum with various anodized finishes.
You can also count the covert but should add the bit about a dealer facilitating the production with Rohrabugh’s blessing. This would count as 2 more models if they were available with and without sights – I don’t know)
That is 55 possible combinations but there are probably more…