The Six-man team consists of the following positions:

Squad Leader - Staff Sergeant
Assistant Squad Leader - Sergeant
Sniper - Specialist-4
Spotter - Private First Class or Specialist
Radio Telephone Operator (RTO) - Private First Class
Scout - Private First Class

The Spotter, RTO and Scout could also be Spec-4. I figured with Basic Combat Infantry Training (14 weeks) + Airborne School (4 weeks) + Ranger School (9 Weeks), there would be no Privates (E1 or E2) by the time they reach Bien Hoa Air Base. Promotion from E1 to E2 and from E2 to E3 are automatic which would take 6 months (26 weeks) to attain Private First Class (E3). E4 requires points. But having attended Airborne and Ranger school as well as being on a deployment to a combat zone would hasten that promotion too. I know I was promoted to E4 after 19 months time in service. I could see a bunch of LRRP grunts making E4 after 12 - 14 months time in service.