With 4 people four crates of guns, Mac-10s. Unless that sea plane had an oversized engine it would be way over Max take off weight.
The Seaplane at the end of the episode carries four people, but an interior shot shows it can only carry two. Where did the others sit?
They most likely were traveling (very uncomfortably) in the cargo compartment behind the pilot/passenger compartment.
It is very obvious the rounds in the belt for the M-60 were blanks. When they are shooting up the boat during the opening scene.
In the hanger scene there is a mirror behind Crockett. On that mirror you can see part of the crew moving around.
T.R. Collins' wife mistakenly calls herself the wife of T.M. Collins.