I just snagged what I thought was a reasonable deal for a 2TB HGST drive. It's a HGST HUS726020ALA610.
What's messed up is that when I plug it in, it says it's an HUS726010ALA610, which is not a known part number.
the drive shows the following in my NAS:
da9 at mps0 bus 0 scbus33 target 15...