I just took a look at my Standard pedal which, as far as I know, is all original and it has a metal linkage similar (possibly identical, I didn't compare them) to that of the Speed King.
Other than the footboard and the color of the paint the Standard is very similar to the Speedmaster pedals. Those pedals use a leather strap and feel pretty darn good, the Standard has the metal linkage and is perhaps the worst pedal I own (as is the hi-hat stand). Perhaps the change in the linkage is the reason.
Looking at the initial Standard catalog it does appear that these started out with a leather strap and then at some point in production switched to a metal linkage.