As they are using “sub-machinegun” instructors, I would say they have full auto M4s.
Read their training requirements, it is not about collecting past due taxes, this is combat training, aimed at citizens.
Training syllabus:
https://www.irs.gov/irm/part9/irm_09-002-001.html#d0e613
Actually, giving SMGs to novices is an advantage for those they come to get. They will be out of ammo in a few seconds. Then walk up and club em while they fumble for another “clip”.
Training, Sir.
MILITARY TRAINING!