In a way, but in Linux block devices can still be accessed as block devices, while in FreeBSD (since around 1999) they can't - there's no caching at that level anymore; raw devices (which Linux got a few years before that) are the only kind of devices. (If you do "ls -al /dev", you'll still see block devices, but it's maintained only to pretend to userspace, just like major/minor numbers.)
Tapes aren't block devices at all - that's why you can't mount them :-)
Mounting and a device being a block device or not had zero relation in classic unix though :)
Tapes by nature are block devices due to only being accessible in block increments, and writing them in transparent way is a bit more problematic than with disks, as being able to just re-read a block to do read-update-write cycle isn't guaranteed - or necessarily easy.
And yes, there used to be a time where you could mount tape as filesystem ;)
