I used to see them in the early 60's in magazines and ar car shows. They were a bit different with the tri pod sens support with the logo in the center of the lens, and some of the high beams were unfluted (clear) lenses, so they had a different look. Especially when in the US only sealed beams were "legal".
They came out on upper end British cars in the 1940's. In the 50's the ever popular PL700 version came along and guys started using them on Customs in the 50's. Why? Cuz they look Bitchen.
While they may look bitchen, Lucas illumination components should only be used on a car that will never be driven after dark. "Prince of Darkness" for sure.