You're right, but I've noticed something strange with my other rig running on Sapphire rx560. When I'm replacing the bios with the ones downloaded from here, it gives different information about the bios (I'm using atiflash with CMD, where full BIOS info is visible). When I replace the original BIOS with such made by me (basically extracted the default bios ,made some mods and flash it back), the information about new and old bios is the very same, so you're right, there's difference among the same vendors, but for me, it worked. My modded bios is crappy, nothing happens when tweeking with AfterBurn and with the ones from here I got good hashing rate. Have to note that the uploaded bioses by privet are with already clocked memory and core.

Back to the MSI topic.

Here's the original ROM: http://s000.tinyupload.com/?file_id=91214473661273445192

Here's my modded ROM, which is doing about 12 (dual mining):  http://s000.tinyupload.com/?file_id=00070263020219795327

If there's some who could mod the original, I would be very happy or share its modded bios for MSI. I see @cchouse did a good job, but he's no longer active