I don't think there are recruit fore arms. I may be wrong but I think the forearms have there own name so no correlation to core and helmet types
All the "default" Halo 4 equipment is labeled "Recruit." So there are helmet, shoulders, forearms, chest, full legs, and the visor color (but we don't need a pep file for that obviously). Currently the helmet, forearms (which as was pointed out, you made the model), chest, and shin are all available in the database under Halo 4 > Infinity > relevant category. Still need the shoulder, bicep, handplate, thigh, cod/buttplate, knee, and boot for the Recruit to be complete. Need a lot more files per configuration with the Halo 4 armor, as only the undersuit itself is in any way "standard." While Reach had a basic bicep, forearm, chest, thigh, shin, and boot, and Halo 3 was even more simplistic than that, Halo 4 does not re-use any pieces. Every shoulder piece has a unique bicep cuff that it attaches to, every chest piece has a unique ab plate (or plates and even cods in some cases), every forearm has it's own hand plate, and every leg configuration consists of a unique boot, shin, knee, thigh, and back/butt plate. And with 343i not showing any indication of expanding theatre mode capabilities, it makes getting reference pics that much harder. Hopefully now that things are getting back into full swing around here people will be more motivated to gather reference sources for their desired armor. I know I've been lax in that department myself.