In case anybody else needs it, I put all the places listed as performing marking services on MSPD website on the map:
Federal Firearms Licensees Providing Maryland Mandated Marking Services - Google My Maps
Built 11/09/2022 based on https://mdsp.maryland.gov/Organization/Licensing%20Division%20Documents/FFL_Marking_Service_Providers.pdfwww.google.com
FWIW, "The Gun Shop", 1614 Eastern Boulevard, listed in your link, and on MSP website, does NOT do any engraving.
Told to me directly (in person) from store owner, "Bob", 12/17/2022.
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