I hear they're running about 3 months right now. The check being cashed doesn't mean anything. The check gets cashed in ATL, and then the paperwork gets sent off to NFA.
I did a form 4 back in October and it took 76 days from door to door. I got the paperwork in before the Obama craze though.
At about 2 months I'd call, with serial number and information in hand, and ask about the progress.
Then, keep waiting.