kansas_volunteer says he has received copies of Man at Arms with Tait's articles and will report on what Tait gives as source information on the 382 rifles at Harper's Ferry. In the meantime, I found that Moller has provided the likely source in his chapter on "Model 1803 Harpers Ferry Rifle."Not having access to Frank Tait's article, I don't know what his source is for 382 rifles being in Harper's Ferry when Lewis visited and how they are identified as some of the 1792 Contract Rifles.
This is from Moller's Vol. 2, page 337.
So the rifles were moved from other repositories in Virginia to the new storage facilities at Harper's Ferry.
Interesting that Moller considered that they may have been rifles from the Revolutionary War!
He also acknowledges the other possibility that they may have been 1792 Contract Rifles from Wayne's campaign. Does anyone know what units were from Virginia that participated in Wayne's campaign?