Yes you can, Migrating the level will move everything that is referenced by that level to the other project automatically, including any actor class that is placed in it.
Jus right click on your map > asset actions > migrate. Select the content folder of the project you want to migrate your map to.
To avoid issues with the migration make sure that the target project has the same engine version as the project you are migrating from. Migrating from older versions to newer ones might work but its not guaranteed.