Yes, you can boot off it provided you select Active and allow it to write the MBR upon restore (as you no doubt are doing). The drive path is arbitrary (relative actually). Actually, when you boot off that restored drive, it will show up as C: instead of whatever you choose at restore. Drive names are not stored on the disk, however, labels are.
Whatever you label the drive, it will stick. The drive letters are assigned by the loaded OS. They will essentially float.
