The slides are identical, just with different sights. The grip on the "Austrian" G22 is nowhere near the size of a G20/G21...more like the grip fills the web of the hand more. The "larger" grip G22 is still manageable for my hands, but it definitely has a larger feel to it. When both guns were laid one over the other, the front of the trigger guard looks further forward as well. When viewed side-by-side upside down, you can see the "swell" of the rear of the "Austrian" grip quite plainly.
Damndest thing.