Different rear bearings for same part # - help IDing correct one? Options

[HectortheRican]

I'm replacing my wheel bearings soon, so I ordered some timken replacements. I got them (ordered part# 512137 x2 for rears) and they're different! Here are some pics.

Here are the two and their differences.


Funny thing is, the only real difference are the locations of the smoothly-machined races. Height and inner diameters are exactly the same, give or take 0.0005", which is reasonably for bearing press-fit tolerances (had some calipers handy) and the bolt holes line up perfectly.

Here's the stamped number for the bearing on the left:


And here it is for the right:


So are these the same? The spindle goes through the bearing and is secured on the other side... so could I actually use both of these?