WTF they checking your paperwork for? Fed law makes it clear that only an ATF agent can check a tax stamp. Does your local range make you provide your 1040 too. It would be GFYS response if they asked me.
How the hell is a range responsible if an individual has an illegal weapon? They aren't empowered to check the legality, nor are they accountable to any agency for that.. All that bullshit sounds like a snowflake is running your range and some know nothing lawyer is advising him.
Letting turds exceed their authority only encourages needless poorly thought out restrictions that go above and beyond reason.