How exactly do you date your Demons, Jimbo?
I can see from your OP photo that the 1920s model had a concave wedge, and the 1900 model was a flat top. Other than that, I am not sure that I am necessarily looking at the correct features when trying to distinguish one model from another.
Would I be correct in identifying the racquet below as a 1910 model?
The wood on this well-worn example had dried out and become delaminated in several places alongside stress splits; which someone had attempted to repair eons ago by installing a couple of screws/pins in the affected areas. This particular Demon had earned its permanent retirement long ago, but I still love the way it looks.
By the way, regarding those pesky moths, the most effective way to deal with them without resorting to potentially harmful chemicals is to put the affected items in a freezer for a week, thaw them out for a few days, then freeze them again for another week. This should kill all the larvae and protect the items from further destruction, so long as the items are kept in an air-tight container afterwards. I do this to my woolens whenever I suspect the airspace of my man-cave has been breached by these evil creatures. I believe that if you freeze and thaw the tennis balls gradually (by transitioning them through the refrigerator?), there should be no harm done to the rubber parts, though you might want to test this out on one ball before committing the whole collection.