Not a rumor. Also the only currently active USN vessel to have captured an enemy vessel during time of war.
Yes. And No. USN changed over to the L80 from the L70 patterns (also to 40x365 from 40x311).
That story may be a bit blurry as the last US AFV with a bow gun was the M-47, which only soldiered on in NG use into the 60s.
Most of the M3 is US armor after about 1965 were M3A3, which had two detents on the port cover to hold the bolt either open or closed. M3A3, IIRC sis used a ball detent and not a crimped lip. Interesting sidebar, by Contract, the tank manufacturer had to provide all the things needed in a track on delivery. So, they are the ones who contracted for the M3s carried, and the non-standard mag bags, and every tool roll, and the like, too.
They were really pretty good for Europe. The ERDL green were scary good in the tropics. Woodland pattern evolved out of the "brown" ERDL used by the Rangers for a while.
I went from OD Utilities to Woodland, to Chips, to DCU, to blueberries, and a single set of avocados. That photo over there at the top left is in blueberries.