Thats true, but there is no point to assembling it with springs that you can verify will bind by their specs.
I could have put a big cam in my LS and checked the springs, or I could check the max lift spec for the stock spring and know ahead of time that I needed to change them. Saves a lot of hassle to not assemble it and have to change them in the engine bay.
LS springs are well defined. Maybe lift specs for the older springs are not as defined and/or consistent, but I would expect there to be a common rule of thumb for the max they are capable of.
