I have not changed the deck gun's property's myself no.
I play Fall Of The Rising Sun V1.5 (PTO U.S.) with RUIM and the Office links & .50 Cal mod, New Narwhale 1.8.4 and TMO interiors with several sub skin mods. The only modding ive done myself is put a 40mm AA gun on an S-42 class boat and figured out the rotational values of said weapon so it'd rotate 80 degree instead of 35*

When i was saying my crew fires wilder than a drunk Cowboy shooting at a rabbit i was being truthful but thats because i have a green crew right now in my current boat and they really are THAT bad.