You have to look at this jumper as a whole:
1) The SSS
2) The community strip and I am surprised that the state strip is missing but this is common.
3) All of the piping is reduced to Two lines if it was Navy it could have two on the cuff and three on the flap
4) Sadly you did not show the back as the stars are most likely removed and or covered by bugs ( little sea scout emblems or missing altogether )
5) it is common were military uniforms are a close match to see them used as BSA uniforms, as to the comment on campaign hats the Boy Scouts had official authorized uniform items from the very beginning of every program they rolled out and it was always stated that to be in uniform you must be wearing Official BSA gear. There was a grey period early were you may have worn what was available but in an effort to copy the British Boy Scout program not the US Army