For what it's worth:
In Nevada individual handgun registration is required for residents in Clark County (Greater Las Vegas area, including Hendersen and Boulder). For a purchase, the dealer give the "blue form" to the buyer after NICS approval of the sale, and buyer has 24 hours to take form to local police or (in Las Vegas proper) the Constable's Office. For a new resident who already owns a gun, the blue form can be had at local police station/detachment (or Constable's office), and form must be filled up and returned within 24 hours, with handgun/s available for inspection if required (leave 'em in the car, don't bring into the station). So far as I am aware, there is no fee for this.
Purchase receipts are required for new hadnguns, but not for handguns purchased outside of Clark County. I know someone in Vegas who tried to comply with a handgun long unregistered, and he had to pay a fine because (I think) records check showed he bought the gun some years before, while he was a Vegas resident already. But he did not get into any hot water, just an administrative fine (I think it was $55). Tried to claim ignorance of the law, but it didn't work.
I would imagine a quick call to the local PD or SO in your area (MO?) would tell you more about the process there.