Plug the gpu into the second gpu slot. Most times that works to get the gpu recognised by the bios and the correct settings and voltages and links applied. After it boots, a couple of times, then you move it back to the primary slot.
The other thing that sometimes happens is there's a pin#20 issue with DisplayPort. It hangs up the boot process by refusing the handshake and you get a no boot vga error. Thays easily fixable by using hdmi temporarily until the gpu is fully recognised by bios.
And to answer the original question, yes and no. The bios on the board is whatever it was at the time of manufacture, which if it's a B450 was quite some time ago possibly. So it should work with any ram etc that was out at that time. Since then there have been farther updates and Agesa updates and fixes for newer ram and other bug fixes, which you won't have. So while ypu may not Need a bios update, it is Advised you do update to the latest non-beta as that'll have the bug fixes and broadest compatibility.