I can't really answer your question about the nut, but I am of the opinion that if you need a grip associated part for a standard AK, don't try to use anything from a MAK90 unless you don't mind spending time trying to make it work. My experience with a supposedly MAK90 grip part was a little aggervating and IIRC, the MAK90 grip needed a shorter screw or something. I have never owned a MAK90, but I found out they were different when I ordered a generic 922R grip from interordnance. When I got the grip, the screw from the romy kit wouldn't work and I had to go buy a different screw at the HW store. Again, IIRC, it wouldn't tighten up and was not at the same angle. Interordnance made no mention about this and wouldn't take the grip back. I found out later through some gun forum that those Interordnance grips were supposedly designed for MAK90 conversions and that seemed about right to me. I did finally get the grip to work and it is still on the gun..... HTH