Found the other bolt. It was just buried under a mound of dirt.
Now, unfortunately, after all of that, the new solenoid doesn't do sh!t. I turn the key and get nothing. I double and triple checked the connections, and they were right, but still no power. Put the old solenoid back in and it fired right up.
Oh, and in the process of double and triple checking and getting pissed off and in a hurry, I got some nice sparks twice
So I guess my only option is to go back to the parts store and get a new solenoid and try this again later.