About 4 months ago I purchased a "Western Digital Elements 500GB" external HDD. For various reasons, I decided to void my warranty (by breaking the seal on the enclosure) and remove the drive (SATA) and install it to my mobo internally. It works fine, but it is recognized by device manager as "External Disk 0 ATA Device." Not too surprising, but here is the really weird part. BEFORE I hooked it up via SATA, while it was still in the enclosure hooked up via USB, it was recognized as "WDC WD5000AAKS-..."
So the drive was recognized for what it is (Western Digital Caviar 500GB) while in the enclosure, but now that it is mounted by itself internally, it's recognized as a generic external device?
some external drives, esp WD & Segates, have modified firmware on them for use in their enclosure. So what you are seeing is the bridge chip reporting the drive name vs what sata is able to get from the drive itself. It should still work fine internally, though not all external drives do.