Mike,
Yes, the upper assembly is called an auxiliary (or helper) spring and is a factory option. I have those on my '42 half ton and give you more capacity without affecting the ride when unloaded.
Kent


1937 Chevy 1/2 ton
1942 Chevy 1/2 ton
1947 Diamond T Model 509
1951 Chevy 1/2 ton
1950 Chevy COE Model 5700 ~ "Barney" ~ And more pix