Waited for the evening to cool down into the 90's. Deburred the lower bearing support and removed label. Delabelled and deburred seat belt brackets as well only cuz they were sitting right where I noticed them.
Had to up-drill the front edge of the lower support where it matest with the lower fuse skin and the firewall. Cleco'd the support in place.
Dug out the lower bearing block halves. They're suppored to slip in between the center firewall doubler, shown at the top of pic 1 below. Oops. Too wide. The doubler is supposed to be 95 mm wide, but it was 94.49, so relatively close. Turns out the bearing blocks together measure 96.52 mm wide, about 2.5 too wide.
Then I noticed the other issue - the blocks were not drilled from a sitting-flush-on-the-bottoms perspective. With the AN3 bolts in the pre-drilled holes, you can see in pic 3 that one side is about 1 mm too tall. Not a biggie, but these have to match a builder-drilled hole that must be drilled using a template. The template assumes the block halves are sitting flat on the lower support. So if I just drill thru the template, it won't match the predrilled holes.