USPSA Production is not a single action division. So, no 1911 is included. Some Para-Ordnance models are included, but those are double action models. A 1911 can shoot competitively in Limited 10 and Single Stack. It also fits into Limited or Open, just not competitively in the high cap divisions.
USPSA Production Gun List
By the way, I voted "Glock 17". Mine could use some trigger work, but it is currently factory stock.