I would not involve the law. Measure it for overall length and barrel length. 26 inches overall 18 inch barrel. If it fails to meet criteria, dismantle it and store it in separate places, if the barrel is not requisite length I'd destroy it. Order the parts you would need ( a stock, barrel, extended chokes, etc.) to make it legal. Looks legal to me, but don't take my web word for it.
Just don't be too quick to involve the law who have a duty to arrest you if they reasonably believe the gun you posses may be prohibited as a weapon. There are real horror stories aplenty of some good citizen trying to do the right thing and getting all hell to pay for it.
---
I am here:
http://maps.google.com/maps?ll=27.354707,-98.158178