Recently got this helmet and would like to know if it's an unmarked Pittsburg. Helmet on left is an unmarked 377 Pittsburg and one on right is one I need help with. Picture two will show base of insulators. Thanks to Dan Ling, Bob Stahr, and Robin Harrison for their responses. Insulator was probably made by either Locke or Lima, not a Pittsburg. Just got this info from Elton; The one on the right was made by Locke in the early 1910's. Most have the incuse VICTOR on the skirt.