Most modern pistols are, but there's little advantage to +p with the available modern loadings. It just adds more recoil and more wear and tear on your gun. I'd much rather be able to put more shots on target in a shorter time frame(faster shot to shot recovery time) than have a 100-200 fps more velocity on the bullet. The difference in penetration between standard loads and +p isn't really going to have that much effect when you think about it. If a standard load will penetrate 12"-13", that's well into most peoples inner workings and a couple more inches isn't going to matter.
Besides, is anyone going to practice enough to be proficient with their gun with +p loads? You'd go broke!