I think I agree with that and that there is good reason for it....although only two of my rifles are in original flint but that is partly the result of not having much money and only being able to afford the conversions.
First, NE rifles are FAR less common than the various forms of Pennsylvania/Kentucky rifle. The late Bill Guthman posited, and I agree with him, that most NE rifles were made for use in militia rifle companies. All of the rifles I've seen that were originally flintlocks (and I have 11 or 12) are .54 caliber or larger. Most were made in Worcester County, Massachusetts. Outside Maine and some other parts of northern NE, there was nearly nothing to hunt with such a rifle like that. There are more woods and deer in NE now than there were in 1820. I have had at least one NE rifle with militia markings that was made as percussion. As such it must have pre-dated 1842 because that is when the militia was reorganized and the requirement that everyone belong to a company and provide their own arms was no longer enforced.
Kent, is your rifle named? I ask because I have one with the identical patchbox. On the barrel it's etched "W. Allen – 1817". I have not been able to pin down W. Allen although I'd guess he was a relative of Silas Allen. Also, the marking is partly on top of a filled-in dovetail so either the barrel was used previously or the marking was added later.