Are suburban and truck leaf springs the same ?

[f.monroe]

I need to replace the rear springs on my 77 half ton short bed that has the factory 56 inch springs. Are the suburban springs in 56 inch length the same as trucks? Same length from perch to eye bolt? I can not find the 4 inch drop springs I have used in the past so I was wondering if the suburban application would be the same . I know they make drop leafs in 52" but I don't want to cut the bed support.
Thanks
Frank