I'm gonna say no. Considering how Mozilla treats the profile mail files as a whole when exporting and importing.
My best suggestion would be to right-clk on the mail you wish to export and choose 'Edit as New' (I always delete the 'Attached Message Part' added by AVG in the upper right hand attachment corner) and re-send it to yourself or wherever you want to receive it. This may be tedious, but it's all I got...