Rbtree
The 365 went through some changes. It seems that the first ones all had the open transfer ports and newer ones have the closed loop, like the 372. I am not exactly sure as to why Husky doesn’t claim that it is a Pro saw. It is the exact same saw as the 372 except for the bore size and a different carb. Yes it does have a single ring piston but so do the 346,357 and they call those models Pro saws.
Your 338 barrel is going through the rinse cycle as I am typing.
Trimmed
I will be in New York on the weekend of the 18th.If you are interested in having your saw ported, I could meet you someplace.
Later
Dan