Bill SC,
I have only seen the ATF at the range once. It was back in the early 90's, they came out to Ben Avery shooting range. Yes, they were checking firearms. I didn't have any Contenders out there that day, so I can't say if they would have "run" it or not. They WERE checking each and every SKS and every other "assault rifle" looking firearm for legality, length, rate of fire, "pre-ban" status, etc.
It was a different regime then, (remember Janet Reno?), regimes can change, policy letters can be written and passed down, for "good" or for "bad". Remember Waco, TX? The ATF was under intense scrutiny after that, and "policy" became more toned down again. It could just as easily be racheted back up at any time, with the writing of another "policy" letter.
Do what you want, risk it or don't risk it, it's your choice. But, why would you want a new shooter/Contender enthusiast to risk it blindly, without knowing the risk ahead of time? Are YOU going to finance their legal battles?
I used to not worry about this subject at all, until I read the ATF policy letter posted on here. Now I make sure there's nothing to worry about. I've worked as an FFL before for many years (not anymore), and I've seen both "good" and "bad" ATF incidents over those 15+ years. I would never want to wish a "bad" ATF visit on anyone.
To each there own, go in peace.