Certainly we see evidence that curly maple became scarce much later, because Leman, Derringer, Tryon and other makers began artificially striping plain maple. I've seen early (1700's) rifles and smoothbores plain (plain for the times) or fancy with all grades of curl. It is harder to work curly maple- much more chance of chunking out a piece if using drawknives, planes and spokeshaves, as they did for most of their shaping, so curl does affect labor of assembly. It's so doggone attractive though, that it became expected by 1800 in a maple stocked gun whether the gun was cheap or expensive.