When I popped the hood, the battery tie down was missing the forward bolt. Now, there really isn't a good reason for this bolt to be missing, just a general lack of attention to detail.
So once we Black Car moved into her new home in the car-hole, I unpacked some boxes and found my bucket of bolts that I salvaged during my AE86 donor car tear down.
A quick dig through the bucket and I found a bolt that would fit.
The battery is now secure, but the OCD part of me is still trying to figure out if I need to go figure out and track down the correct length bolt since this one is likely too long. Since Black Car will never be a Concourse level vehicle, this will probably be good enough.