Hmmm, could it be an aftermarket fascia? The newface fascias use(d) the same plain round buttons as the MkI. They're alumin(i)um, so easy to identify...
here are some newface pics.
In order to 'reformat' - you can apply the
disk builder image (will also remove all music), followed by a software image (as the disk builder nly partitions and formats the drive(s)). Less drastic is to just upload new software (check the About menu to see what's currently running), keeps the music but doesn't reformat the drive(s). The developer editions gives you some handy tools for troubleshooting, so go with that instead of the consumer version even if 'developer' sounds alien and scary
.
Good description of the process is in the
disk upgrade FAQ just skip the physical parts)