Again; yes, and no.
If both NV residents, and YOU do not live in Clark County,(LV); then it's a "clean" private party transfer.
If YOU are a Clark Co resident, and it's a handgun, then you must register it with local PD. (believe seller must verify; ie witness registration, ? or is that just for sale of "registered" weapon?)
Neither of the above require an FFL if both NV residents.
Capiche?