Nope, 3/4 tons are more than just springs. Larger/Heavier parts include: springs (of course), brakes, axles, drivetrain (sometimes: tranny, t-case, universals, driveshafts, ect.), radiators......thats about all that I can think of. I think that 1/2 and 3/4 tons share the same frame, while 1 tons are heavier.
1973 K20 - 350/465/205