Question How determine bios version on MSI mobo without turning on

Looking at the bios update list for your motherboard, the last update that referenced a new cpu was in 2016 and, I think that referenced 7th gen processors.
If you have a new motherboard, you will have the latest bios.
Even a old used motherboard should have supported i5-6600 from the beginning.

My suspicion is that you have a bent pin in the cpu socket. It is very easy to do.
Remove the cpu and inspect the pins.
It is most unusual to see a broken intel processor.
 
If this is a used motherboard, you have no idea what the bios level might be.
It could have the original bios, or the previous user could have updated it to who knows what level.
If the motherboard is new, it will likely have the most recent bios.
In the unlikely event that it is very old stock, you might have something older.
This motherboard was first produced in 2015.
 
I bought this board, as a new one, in early 2016, but I unpacked it just now.
Oh well, am almost want to throw my hands up at that.

Nobody print the BIOS version on Mobo as they are ship out the door anymore. Things move too fast, updates happens too often. Does anybody here, after updating your BIOS/OS bother to document this making a new sticker on the Mobo/Case? if u you do, you are lying.

U have to make an educated guess. When did the Intel Refresh came out? when was the Mobo manufactured? (first sold) if the two numbers are within an 18 months period, u may need an update.

But yeah, as others already mentioned, I'd inspect socket pins.