Let me start out by saying hello.
I lurk in many forums (Guns, Harley Davidson and Corvette's primarily) and don't usually get involved with posting unless I have something to contribute. As this is my first post and I am the individual with the "Special Forces" R9 for sale on Gun Broker I will keep to facts and certainly not try to sway individuals with my bias.
In keeping with the question asked I will only respond to the Wilson Combat "Armor Tuff" question. I have owned no less than 12 Wilson Combats with 8 of them being coated with Armor Tuff. Armor Tuff is put on less than one thousandth of an inch thick and will not affect the operation of the R9 or any gun for that matter as it only tends to make it function smoother. I have other Rohrbaughs and the "Special Forces" is smoother feeling when cycling the slide.
I would suggest going to the Wilson Combat site and checking the write up on the coating as there's many good reasons listed as to why it is desirable albeit it's their product so you would expect that.
As to the other questions I'll have to defer to the experts on why Rohrbaugh only made a limited run of these, I can only speculate that cost is usually the factor.
As I know the question of why am I selling will come up, I'll answer it now. I buy and sell guns quite often with many being what would be called "safe queens". I buy and trade/sell many without ever have taken them to the range, however I shoot at least once a week usually. I'm not a typical collector as I change direction with what I'm buying quite frequently moving on to something else. The "Special Forces" is a fine limited run firearm that I considered a good investment.
Dave