Gigabyte B450M DS3H and GTX-1660 - Will this work?

[iBolski]

My title says it all. I have a Gigabyte B450M DS3H motherboard and a GTX-1660. The motherboard already has rebar support in it, and I've enabled it (only AUTO or DISABLED are my choices, so I've chosen AUTO), along with above 4gb decoding set to true. GPU-Z shows 4gb decoding is enabled, but resizable bar is disabled.

Do I still need to include the FFS module and will it work even though my BIOS already has rebar support in it? I want to know before I flash my updated BIOS image. Also, could this brick my motherboard where I can't get back into it to flash it back? It doesn't have a button like newer motherboards to recover. I would have to boot into the BIOS to do a flash from USB.

Thanks!