The 9/357/40 variants come with Medium Grip Modules but the 45 comes with SmallVery nice!
I always thought that SIG shipped P320's with Medium grip modules. You can probably find someone with baby hands that would happily trade their Medium or Large for your small.
Nope all 45's come with Small Grip Module because the grip is bigger and is a bit closer to the Medium for the other calibers.I wonder if they were trying to use up stock of the older grip modules in that size. I have a fullsize and a carry. They both have the new style Gen2 modules in Medium.