just inside the farmlands region is the ASOTUNGAN OUTPOST co-ords : -244.206 , 2052.486 shows that there are 4 weapons to collect. i cant remember when i picked these up. but i only have 1 / 4 collected and are not showing up so i cant get that area complete.
I reported this as a bug, since the location of all weapons there is known I checked the known locations and 3 of the 4 are simple not there. Probably gone to where the Boo bridge went to. Lol