Montana Jim said:I believe all are WW II era... Two US Army and two navy buttons. All buttons look like "low convex" style (more flat) indicative of WW II era styles. The two "self-shank" (no back mark) buttons may be a little newer, but of the same era.
FYI:
HILBORN-HAMBURGER, INC
122 DAYTON AVE PASSAIC, NJ
07055
800-526-7475
973-773-0593