They are external shoes. Meaning there are 2 lined shoes that work on the outside of a 'drum'. I had a brake and clutch shop re-line the ones on my Mom's BG. (Right side housing identical to both sides of a BF). I did have to get a shoe or a pair of shoes from Bill Williams, Baldwyn MS. I don't have his phone number handy.
The brakes are inside the cover plates (both top and bottom cover plates) on each final drive housing.