It sounds possible under the following conditions.
3.55 is modded
Backup Manager works on 3.55
MW2 works on Backup Manager
Once thats complete I'm sure you could just at the map file to the directory with all the other maps and it should load, but then again, the clients will all fail to load because they don't have the map. Maybe one day more and more people will do this, and the maps might actually become playable ....
And who knows, maybe even custom maps

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