I titled and tagged my 1971 M35A2 at the Bel Air MVA office ~2yrs ago. They were a bit confused about it, however I had an existing PA title and the past owner titled it with the registration number appended to the s/n so it had the "proper" number of digits so I did not have too much of a fight. About 30min later I had a new title, registration and tags.
Also with respect to your safety/emissions/GVW comments CFR, COMAR and MD code are on your side. In accordance with 49 CFR 390.5 (FMCSA) a large MV (or any large vehicle) with a GVWR >10,000lbs is not considered a CMV unless it is used for interstate for-hire activities, and therefore 49 CFR 390.3 (FMCSR) does not apply. Additionally, COMAR 11.21.01.04.b.3 states that MD simply adopts FMCSA's definition of a CMV and again a large MV would not be considered a CMV unless it was used for commercial for-hire activities. The annotated code of MD 13-936.2 expressly permits vehicles with a GVW >10,000lbs to be registered as class L (historic), and 13-396.2(g) states that class L vehicles are only required to have equipment (including safety equipment) that they were originally manufactured with. 13-936.2(h)1 also exempts class L vehicles from any periodic inspections of equipment or emissions controls.
Given the above, meeting safety and emission requirements is a non-issue if you register as historic, and you can register as historic as a M923A2 is not considered a CMV if only used for personal, not for-hire activities. Hopefully this helps your plight.