Wow. A lot of misinformation here.
Agent19's quote is related to someone who has been issued a CCW/CFP but does not have it in their posesssion while they are carrying a concealed firearm. Totally irrelevant to the question.
h2ojunkie is wrong that there is no penalty. Here are the relevant sections of the Clark County Code:
12.04.110 Registration of pistols within seventy-two hours.
Any resident of the county receiving title to a pistol, whether by purchase, gift, or any other transfer, and whether from a dealer or from any other person, shall, within seventy-two hours of such receipt, personally appear at the county sheriff’s office, together with the pistol, for the purpose of registering the same with the sheriff. It shall be the duty of the sheriff to register the pistol, and he may, and is hereby authorized to cooperate in any manner he sees fit with other law enforcement agencies, and with licensed dealers, relative to registration of pistols, so that efficient registration shall be secured at minimum cost and duplication. (Ord. 3571 §3, 2007: Ord. 242 §11, 1965)
12.04.200 Registration of firearms capable of being concealed.
It is unlawful for any person with at least sixty days of residency in the county to own or have in his possession, within the unincorporated area of Clark County, a pistol or other firearm capable of being concealed, unless the same has first been registered with the sheriff or with a police department of any of the incorporated cities of Clark County. (Ord. 3571 §4, 2007: Ord. 242 §20, 1965)
12.04.220 Penalty for violation of Sections 12.04.010--12.04.210.
Any person who violates any of the provisions of Sections 12.04.010 through 12.04.210 is guilty of a misdemeanor and upon conviction shall be punished by imprisonment in the county jail for a term not to exceed six months or by a fine of not to exceed five hundred dollars, or by both. (Ord. 242 § 23, 1965)