Help with Fusebox VW Rabbit 1977 fuel injection

[okimind]

Hello,
I wonder if someone could help me with some information. I have VW rabbit 1977 fuel injection, I am planning to change the fuse box, the current fuse box is part number 171 941 821A. I have a FD-HH fusebox in really good condition. the layout of the pins in the back are the same in both boxes, the only different is that the FD-HH doesn't have the pins in the B section (It does have the holes for the pins, the same layout as the 171 941 821A box) they are only 6 pins in the B section.
My questions are: Can I use this FD-HH fusebox to replace the other one? if I can, where I could find the back pins to add to the section B (I have been looking and I can't find any information)? If I get the pins I just push them into the holes? or is there something else that i have to do?

Any information will be greatly appreciated. Thanks for your time!!!!!

Best,

Oscar