Hi Rick,
Before you try and sell this pistol with it's detachable stock, you'll want to ensure that it's listed in the ATF Curio and Relic List:
http://www.atf.gov/publications/fire...elics-list.pdf
There are several permitted combinations, but you need to verify the details of what you have in hand against the list.
If the combination you have is not exactly described on the ATF C&R list, you could have problems because having the wrong stock and pistol constitutes a Short Barreled Rifle, and is considered NFA Class III.
You may not have an issue at all since the pistol doesn't appear to have a stock attachment lug, and could not be used with any stock in that case.
Marc
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Igitur si vis pacem, para bellum -
- Therefore if you want peace, prepare for war.