N.H. Rev. Stat. Ann. § 159:13

No person shall change, alter, remove or obliterate the name of the maker, model, manufacturer's number or other mark of identification on any pistol or revolver. Possession of any such firearms upon which the same shall have been changed, altered, removed or obliterated shall be presumptive evidence that such possessor has changed, altered, removed or obliterated the same. Any person who violates the provisions of this section shall be guilty of a misdemeanor.