Neg. Battery Cable

I'm replacing the battery cables on my /6 1975 Scamp. Positive is done, now negative. It seems as though I have to remove the power steering pump to remove the bolt holding the original. I'm wondering if that's the original attachment location. It seems like an asinine place for connecting the cable. :-k I have the pump loose and ready to pull, but before I do, I thought I'd ask you guys.
Also, why do the older mopars have only one negative connection (to the block) and this has one going to the firewall as well?