I believe this is a model 6601; 20" heavy barrel, 1/7, large pin lower, no mag fence, no sear block, low 4 digit serial #. I've heard these refered to as transition models(?). The forward pivot screw has been replaced with a quick removal pin, and the grip replaced with a walnut target grip w/ adjustable palm rest. Original parts will be included along with a factory 20/5 rnd magazine. No box or manual. Condition is very, very good with some minor safe storage marks. Asking $1150/OBO plus shipping to your FFL. Sorry, not interested in trades at this time. E-mail for pics, etc. at email@example.com. Thanks.
Also have a FNC available in Rifles/shotguns.
Edited for model and price.