Originally Posted by Goosehead

one I seen has a round trigger guard and the other has a round trigger guard?

Well...they're the same then.

-Jeff-

One was round and one was square. Any difference?

I have seen a "new" (I think) version of the 5906 that has a light rail in it. I have an old 5906 that I bought used. Its heavy but it is a great gun.

The square trigger guards were primarily for law enforcement. They have more room in front of the trigger for use with gloves, and most of them have crosshatching on the leading edge, for use by the index finger of the left hand for stabilizing the pistol when firing. That was being taught in many circles then. I still have a 6906 in that configuration. But I personally prefer the rounded version for civilian use.