Jim
The slide stop pin is shortened as an enhancement being used as an option for high dollar 1911, it changes the look of the 1911, also it moves the pin back if your using a laser grips, and it also allows a person to practice point shooting techniques with out the probabilities of accidentally pushing the slide stop pin and pistol disassembling while firing the pistol.
http://www.pointshooting.com/1aversus.htm
Cuba