If or when you/or I, don't care about org. exact looking factory bolts,
like on a rest-mod or projects
I buy Stainless Steel (use anti-seize if using in different alloys),
& use a hardened countersunk/beveled style radiused washer
or matching stainless
(or stainless Nylock type nuts), with most everything I can,
extremely hard & strong, no paint needed or any rust issues
I do like the 12 pt heads, easy to get in small places,
smaller socket or wrenches required in tight places, looks great too
or
a lot from ARP, rolled threads, not cut
order on line, specific shank & thread lengths, head styles, matching beveled washers
or
Fastenal at the local store, they love me