What do you mean by electrical side covers? Are you talking about the engine covers -i.e. alternator cover? I'm not sure what parts on a 79 are interchangeable with a 77. I can take measurements for you, or you could ask the knowledgeable folks on the forum, maybe in the main part of the forum if they know off the top of their heads.
I have a couple extra batteries, but I'd have to drain the acid first. You'd need to refill it. If that sounds like something you're interested in, we can get details sorted out. Let me know. Thanks.
I'm 99% sure the side cover is in good shape. I'll check it with a multi-meter tonight to make sure it's still within spec. Email me your phone number, and I'll call you this weekend. bosco391 -at- yahoo -dot- com