1 ton springs may be either 52" or 56" between the mounting points, but are usually 56". The 1/2 ton should have 52" springs.
If you find that the 1 ton has 56" springs you may be able to still make the switch if you can also move the mounting brackets. However, the 1 ton frame is thicker and I'm not sure if that affects how the brackets are bolted on.
Also remember that your truck may get some lift, but it will also ride a lot stiffer.
Bruce