Old Bay is much more recent. It's based on a lot of spice blends dating to the mid 19th century but Old Bay in particular is only from the 1930s.

It was originally for crabs, and that particular dish really is a distinctive local tradition. Applying it to everything and calling it "Maryland" really only dates to the 70s.

Lawry's Seasoned Salt for chicken.

The local spice tends to be JO.