It is a legal requirement for firearms in NZ to have a serial number (Arms Regulations 1992, Section 12) even though there is no registration for A cat firearms (I often use the date of completion for any I manufacture, eg; 120718). It has always been a popular thing in US based web sites to delete the serial number of firearms in photos. I don't think it has any particular relevance in NZ but there is always some arsehole looking for an angle so it probably pays to exersize caution.
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