The stocks are basic and straightforward in form. They will almost invariably have the characteristic small rounded cheekpiece. The double sideplates (the "lozenge" and the "comma") are typical, as is the barrel tenon/rod pipe pin arrangement. Cherry wood is probably the most commonly seen stock wood. Rarely carved, but often seen with wire inlay, particularly around the breech tang, and sometimes with checkered wrists.
My rifle is about .58 cal., which is quite typical. The barrel is more or less straight at close to 15/16" and is 41" long. Mine has a round bottomed stock and fowler-type hardware, but the typical "militia pattern" rifle hardware is commonly seen. On this gun of mine, the trigger is non removeable. The pin hole is not drilled all the way through the stock. I don't know if this is typical for Mass. rifles. The two sideplates are cast brass and THICK. about a quarter of an inch. The fore end is full and round and doesn't step down much at the rear rod pipe. Many more N.E. Rifles are half stocked with wood ribs. I believe the wood ribs are tenoned and pinned on just as if the barrel were in a full stock.