Mail "import" from MAIL

My old imac died so I removed the hard drive and have mostly succesfully ported everything to an old mini. The one issue i have is with MAIL. I have copied over everything and placed them all in the right place but MAIL cannot see the old accounts, settings or mail in the accounts. I don't mind re-doing the settings but I would like to retrieve my old mail. MAIL's wizard sort of offers to import but it doesn't offer MAIL as an mail app to import from? If I switch to another mail app, will it import>? Thanks.