Help with Brake Booster and Master Cylinder

[ogsRULE]

I got my truck as a project and am still digging through the boxes. One problem is that the boxes have parts from two rigs that were torn down and I don't always know which is which. Right now ready to put the brake booster and master cyl at the firewall and having trouble sorting it out. The bracket set ups for either booster don't seem to fit the firewall.

See pics. First is the firewall. Sorry, three tries and it keeps rotating the shot. , second, and third are the booster and master cyl assembly. The bracket seems to have been drilled, but does not seem to fit the firewall. Next two pics are the other assembly.

Any ideas here? I hate to start drilling. I was going to replace the master cylinder anyway cause it's been sitting for four years, so maybe ahead to just replace the whole thing?

Thanks,

Scottie