This was originally a post that the E2 grip won't fit, but I went back and messed with it some more and got it to fit. You have to take the hammer strut and hammer strut spring from a P226, along with the E2 grip, and swap it all. The E2 grip won't fit with the stock P762 hammer strut/spring in place (see pictures below - you can see the lower profile and curved back of the Sig hammer strut). The Sig hammer strut takes a bit of finagling to work in the P762, but it does. After swapping that strut in, the E2 will fit, but
barely. Snaps into place a lot harder, and is harder to get back off, than on a Sig 226. As per the other image earlier in this thread of the standard Sig P226 grips, the E2 grips don't cover the whole handle but it does fit and I like the feel of it.
It looks like the Sig P226 E2 grip kit comes with the required hammer strut, but not the hammer spring, so that would need to be source separately / elsewhere.
At first glance the internals look VERY close to the P226 - I'm wondering if the Sig P226 SRT kit would fit?