I understand that you want to know if you receive a motherboard with an older BIOS version, can you update the BIOS with a newer processor.
In regards to your inquire, usually you will be required to have a supported processor to update the BIOS and then you can upgrade the processor.
If you already have this issue, sometimes a BIOS recovery update can help you go thru the update.
Thanks a lot! I think I'll buy a board with B75 Chipset instead.