Possible bug with migration backup file

I've been testing the 2.0 migration for my site. After migrating my staging site I decided to revert back to 1.7. I used the zip file that the migration plugin created. All of the directories in the zip file came back with permissions 777, instead of 755. I had made a tar file of the site before starting the migration, so I deleted the restored files and restored from my tar file instead; permissions were correct in the tar file. All is well, the site is restored and working, but I wanted to let you know about the issue.