Regarding Covering Firearm Serial Numbers in California
This article arose as a direct result of Calguns' Lormic answering a question on covered serial numbers during an open carry discussion
Within the Californian Open Carry community, there are many folks who advocate covering serial numbers of weapons while open carrying. What's important to note is that this is NOT just a firearms offense; it's actually a general offense for manufactured items. It could apply to cars, computers, etc etc. There are two sections of penal code which apply to markings, however 12090 does not apply to covered markings, which is the subject of this article.
What's interesting is that although the offense never exceeds misdemeanor level, the value of the gun changes the maximum sentence. For items valued under $400, the maximum sentence is 6 months. For items valued $400 and over, the maximum sentence is one year. Therefore, if you INSIST on doing this with your gun, use a cheap gun.
(a) Any person who knowingly buys, sells, receives, disposes
of, conceals, or has in his or her possession any personal property
from which the manufacturer's serial number, identification number,
electronic serial number, or any other distinguishing number or
identification mark has been removed, defaced, covered, altered, or
destroyed, is guilty of a public offense, punishable as follows:
The most accessible exemption is found here, for weapons with visible serial numbers:
(c) This section does not apply to those cases or instances where
any of the changes or alterations enumerated in subdivision (a) have
been customarily made or done as an established practice in the
ordinary and regular conduct of business, by the original
manufacturer, or by his or her duly appointed direct representative,
or under specific authorization from the original manufacturer.
Firearms Without Readily Apparent Serial Numbers
Certain firearms do not have readily viewable serial numbers. Certain Smith&Wesson revolvers have their serial numbers underneath the grip plate. Others (my wife's S&W 686 for instance) have the serial number covered by the revolver's cylinder during normal operation, however this would become visible during a 12031(e) "loaded check".
Other firearms may not actually have serial numbers at all. Prior to the 1968 Gun Control Act (GCA), serial numbers were not mandatory on firearms. Most firearms did have them though, for warranty and tracking purposes. Pre-1968 firearms are still legal to possess, sell, etc.
If you built your own firearm, it does not have to be marked with a serial number, place of manufacture, etc. However, should you choose to sell it at a later date, it must be marked prior to sale. This does not mean "I bought a frame/receiver and assembled the parts onto it", it means "I machined/bent/etc the frame myself from something other than a completed firearm receiver".
Dependent upon the placement of the serial number, a laser or tactical light may cover the serial number on most handguns. Mounting accessories, particularly rail-mounted accessories, would fall under the customary exemption: "have been customarily made or done as an established practice in the ordinary and regular conduct of business". If your weapon has a rail mount on it, it's a very established practice that people are going to mount accessories on that rail.
As noted above, a firearms manufacturer or their direct representative (perhaps, for instance, certain gun shops may qualify) may authorize the covering of a serial number. It is advisable to get this authorization in writing.
Non-Chargeable Penal Code section: 12090
It's worth noting that the section of PC which folks tend to think of for this does not include 'covering' markings. It essentially covers removing markings, as referenced in the quote below.
PC 12090 states:
Any person who changes, alters, removes or obliterates the
name of the maker, model, manufacturer's number, or other mark of
identification, including any distinguishing number or mark assigned
by the Department of Justice on any pistol, revolver, or any other
firearm, without first having secured written permission from the
department to make such change, alteration or removal shall be
punished by imprisonment in the state prison.