No Idle Adjust Screw

"My 912is is a bit older, was this an update (I have not been able to find any info)?  Would adjusting the black screw on mine to slightly increase the idle be a mistake?"

No. I have had some 912iS engine's that the idle was so low it vibrated like crazy down around 1500 rpm or less. That screw is hard to turn cold  and it could be broken off if not heated. I remove the plastic cap, heat the screw and then it turns easily. 

I have a small pencil tip butane torch that has a small, but very direct-able flame to target a specific spot. A heat gun heats an entire area and sometimes I don't want that heat on other parts. So the small pencil tip torch only heats the target area I want and not the surrounding area.