You could open GPU-Z and look at the BIOS version then flip the switch and look again. It shouldn't be the same BIOS version.
Gpuz will show one bios, don't matter what position the switch is in.. it'll be the same number..
only difference is what's in the sub bios that makes the card react different.. ie a fan curve or a bump in frequency is all...
Usually one bios is the back up and the other is for a slight performance increase.. Back in the R9 days I got 2 custom bios's from MSI.
They were identical numbers and only difference was one was stock, (977MHz) and the other was the (1003MHz) all tied to what the gaming app would bump the clock speeds up to.
I didn't want to use the gaming app and a friend that used to work for MSI got the bios for me.
I gave it to W1zzard to go over and he couldn't tell one from the other besides bios#1 and bios#2 and then he posted it to the gpu archives.