CA DHCD, Div of Building & Housing Standards plate Oct 24, 2017 9:55:45 GMT -8 Quote Select PostDeselect PostLink to PostMemberGive GiftBack to Top Post by tehachapibob on Oct 24, 2017 9:55:45 GMT -8 Does anyone have knowledge of the abbreviated designation on this plate?There is the following section:M- unknown; possibly the year of manufacturer or model . My plate had 66 here but my registration is for a '69.S- I'm pretty sure this is for serial number as it matches the SN on the trailer tongue.Plg- maybe for plumbing type? Mine was blank.Htg- maybe for heating type? Mine was blank even though it had a gas heater.El- possibly some inspection code for electrical compliance. Mine was blank.My main concern is the "M" definition. Any help would be appreciated.