Yes fut there a restrictions on sale of said firearm.
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.
NO, there isn’t, more than any other firearm. Please stop spreading misinformation so insistently.