Pretty sure you are right that A and AB are tip types:
https://www.instockfasteners.com/tools/screwpoints.ASP
bndr-hd I think is 'binding head' a very flat wide head
I find Marco has a lot of these parts with good descriptions. For instance, 4106-01042-20 is SHEET METAL SCREW #6 X 1-1/4 INCH P-FLH-A, where the P- is "Phillips".
See here for some of the set screw acronyms - https://www.marcospecialties.com/pinball-parts/4008-01083-06