The original "Main with No Name" spurs from the Clint Eastwood "Dollars Trilogy" of western films including "A Fistful of Dollars", "For A Few Dollars More" and "The Good, The Bad, and The Ugly.
Not much is known of the original spurs. They might possibly have been brought to Spain by Clint Eastwood who originally sourced his wardrobe from local shops in America and from pieces of wardrobe he'd used originally on the series Rawhide.
It seems highly likely that the spurs may have been sourced from Andy Anderson who sourced them from "North & Judd" (aka "The Anchor Company"). North & Judd was the manufacturer of the original holster buckle that was used by Andy Anderson for Eastwood's Holster.
The oldest manufacturer in New Britain, and one of the oldest in CT., North & Judd’s business and identity evolved over decades before incorporating in 1863. - New Britain Industrial Museum