Automotive question: BMW battery leads

An older BMW needs to stop gracing my life. In order to help it on its way, I need to give it a jump start.

No problem, right? I’ve got the cables and my current car, which I’ve only had a few weeks, is running fine.

So I park the new ride head in with the old, and for the first time since I bought it, open the hood. Where in the heck is the battery?

It’s a ‘99 740iL, and there is a plastic cap labeled “BATT +” on top of the engine, at the front end of the left valve cover. Opening that cap, I see a bolt with a sort of a battery cable lookin’ thing attached. No clue where the battery might actually be.

So, am I correct in thinking that I can attach the positive jumper cable to that bolt and attach the negative to something I believe grounded, like the engine block, and jump the older brother?

Yes, that’s the correct way to jump it. The battery is in the trunk to help with weight distribution.