i have been looking to buy a 320 compact, but have noticed 2 different looking frames. Under the slide release a protrusion that goes a round 3 sides and on other frames just one under the slide release. The lgs guy tell me they are the same, but is one the newer model? and if so which is which.

The newer model 320 frames have smaller recesses for the slide lock levers.

However, the older P250 frames also work, but will not fit current magazine base pads. FYI

Thanks for the tip on the 250 frames. I have a spare compact frame with half a dozen mags. An SC 320 would give me a great configuration.