Hi Blackwater ... I've never seen leaf springs with zerks - interesting. What I do find fascinating are the apparent myths and legends around the demise of wrapped and lubricated springs:
FAQ Eaton Detroit Spring
Engineering Forums (TIPS) circa '12
I am baffled by the idea that lubrication could somehow break down steel. But I have indeed driven vehicles with 'dry' leaves for decades - so was lubrication ever needed in the first place? Never gave it much thought until I started working on a forties era car.

regards,
stock49