I'm working on building an SG from a Pit Bull kit, I measured out the scale length from the nut to the bridge and it measures at the correct 24.75", but the guitar's neck protrudes about 3/16ths of an inch into the routing for the neck pickup. Is this correct? For some reason I can't attach a picture so here's an imgur gallery of how it looks.
You'll need to reduce this size of your pic a little to be able to post. Max size is 1500 pixels high and 1500 wide. Yours is too tall ;-)
The measurement should be from bridge side of the nut to the neck side of the high E saddle with the saddle adjusted all the way (or almost all the way) forward. Basically from where the the high E string leaves the nut to where it joins the saddle with the saddle all the way toward the pickups.
In the pic it looks like the bridge is not in place. You'll need to have it installed to get a good measurement. Hope this helps.
I think what I'm going to do, since the scale length measures correctly and the neck is already set in, is I'll just dremel off that extra 3/16ths of an inch since it's just the end of the fretboard. With a steady hand, I should be able to do it without it looking too bad.
I did something similar trying to fit a Jazz bass neck on a ES335 body. It looks like you might have to take off a bit more than that to accommodate the pickup ring.