I actually have other optical drives that have a very short case like the Lite-On 52327S that aren't made by Lite-On.
Check out these pictures:
Notice that the headphone connector and the emergency eject hole are in different spots and that the Lite-On has one button and one LED while the MSI has two buttons and two LEDs.
The back of the MSI drive is different from the Lite-On, too. Note that the small block of pins which aren't normally used are in different places. Edit: Actually, none of the connectors are in exactly the same places.
The top and side of the Lite-On drive looks very different from the MSI, too. Edit: Note the number of "dents" in the top of the drive and the small cut-out on the side of the Lite-On.
Basically, my point is that the MSI and Lite-On have so many physical differences that Lite-On would have had to have significantly re-designed the drive if they had made the MSI drive. This is why I don't think they're the same.