I was on a rooftop in midtown recently and had a good view of the top of 570 Lexington Ave, originally the RCA Victor Building, later the General Electric Building. The national register designation report suggests that the figures represent spirits of electricity, although the lightning bolts maybe represent electricity and maybe represent sound waves. (Also note the row of smaller faces at the top of the solid wall.) Metallic glazes (aluminum and gold) were used on the terra cotta to make it really shine.
To give a sense of how slender this building is and how te crown stands out, here’s a long view courtesy of Intern1999: