Help with OEM colours and leather types

I am about to purchase a new 6 speed illuminated ///M gear knob and a replacement leather boot for the gear shift (neither are in 100% perfect condition).

However, my search through the parts catalogue has turned up a couple of variants in the leather boot area that I am unsure of.

The options appear to be:
Silver grey gear boot - Walknappa - part number 25 11 1 222 183
Silver grey gear boot - Bison - part number 25 11 1 221 915
Silver grey hell (bright) gear boot - Walknappa - part number 25 11 1 222 152
Silver grey hell (bright) gear boot - Bison - part number 25 11 1 221 887

Can anyone explain to me the difference between 'walknappa' and 'bison' leathers and also, the difference in colours between ordinary silver grey and silver grey bright.

Pics would be helpful.

Thanks in advance.

David