My understanding is that once you have possessed the item for a year, you may sell it. The 1 year period without sale is presumptive proof that you did not “manufacture” it for profit.
That is the period an FFL needs to hold a personal firearm that he obtained from his FFL before he can sell it as a private party, without record-keeping.
How do they know when you “made” it?
This is why I never got a CR license.
The rules are vague at best.