At the first post-installation internal or certificate inspection, the inspector shall assign to a boiler or pressure vessel a Maryland serial number that is: At least 5/16 of an inch in height; Configured as follows: For power boilers <MD> MD 0000; For heating boilers <MD> MD 0000H; For pressure vessels <MD> MD 0000V; For nuclear vessels <MD> MD 0000N; and Stamped on: The boiler or pressure vessel, or A metal tag at least 1 inch in height, securely attached to the front of: A low pressure heating boiler constructed of cast iron, or A pressure vessel constructed of cast iron or other material of a thickness that should not be stamped. Unless a record is kept showing the location of stamping so that the stamping can be uncovered readily, stamping: May not be concealed by lagging or paint; and Shall be exposed at all times. When a boiler or pressure vessel stamp is indistinct: An inspector shall direct the owner to have the boiler or pressure vessel restamped; The owner shall: Request from the chief boiler inspector permission to restamp, and Submit with the request, proof of the original stamp; and If the chief boiler inspector authorizes restamping, an inspector shall: Observe the restamping, and File with the chief boiler inspector notice of the restamping, and a facsimile of the stamp applied. A condemned boiler or pressure vessel shall be stamped with: Letters 5/16 of an inch in height; and The configuration XXX MD XXX.