It should be no problem to copy your mails from one icedove to another. I sometimes copy a Windows Thunderbird profiles /Mail -subfolder into an icedove /Mail -subfolder and have access to all archived messages.
You can test it without corrupting your mails: copy the ~/.icedove/profilenamehere/Mail subfolder and its subsubfolders to a stick, boot a livesystem, install icedove in livesystem, copy from stick to /home/siducer/.icedove/profilenamehere/Mail and open icedove to see if all your mails are there. If so, it should work as well in a real install.