yea, I've done it.
IT does make the parts bigger, and when I do it again, I know now where to watch out for clearance issues.
First of all, I think one should be very careful about adding to the bolt and bolt carrier. specificaly, the area where the bolt slips inside the bolt carrier. I would wrap the cylindrical part of the bolt in black tape, and put some inside the bolt carrier, where the bolt fits inside it.
Also, just leave the foregrip retainer in the position that it will be in while the lower is in place.
And the only other place to watch out for, is the place where the upper handguard is latched by the little lever thingy. I would take file and remove a VERY small amount from there, just to be safe, before plating.
Other than that, there are no other issue which I am aware of. I have done a few of these, and hey alway turn out better than I expected.
P.S> AKs have a lot of slop, and everything fits kind of loos anyways, so I wouldn't worry about anything else.
P.P.S. let us see some pictures when you get done. I have been wanting to replicate that same AK pistol, witht eh gnarly wood grips, goldmedalion, and script.