Thanks, Stewart. I am curious to know Roger Whitney's thoughts on the matter, as he probably knows more about the Monson than anyone else alive.
A big question is whether the bells that Monson 3 and 4 were wearing in the 1930s and early 1940s survived their scrapyard sojourn in Rochester, NY before the engines made their way to Edaville after the War. The "Two Feet to the Quarries" book by Robert C. Jones shows a couple of photos of the engines being loaded on SG flatcars at Monson Junction in 1944 with no bells visible, but that doesn't necessarily mean they didn't go with them. They could have just been taken off for shipping.
Being a fan of the Monson can be a frustrating experience at times because there's so little left of it and so little known -- this despite the fact that it lasted longer than any of the other Maine narrow gauge railroads.
-Philip Marshall