AFLs, by their heritage, will brace at a "D" shape no matter whether the limbs are string follow, dead straight, or with backset.
however, mild R/D hybrid longbows will brace at a classic "D" and show some small amount of limb flip (not backset) when unbraced.
once again, an ASL doesn't properly identify an American Flat Longbow from an ELB. the distinction is in the limb cross section, whereas an AFL is FLAT on both its back and belly, and an ELB is is a combination of a flat back and rounded belly. howard hill made AFLs and he was careful to note they were always flat in limb cross section. but, what's in name or acronym anyway ....