Proportioning valve for drums?

[MightyFine69]

I know this may sound like a dumb question, but do you need a proportioning valve for four wheel drum brakes? The reason I ask is last September I had to slam on my brakes to avoid hitting a tractor that was turning in front of me and my rear brakes locked up and caused me to spin around and flip over in the ditch. Needless to say my truck if not drivable as it crushed the roof. Oh, by the way, my brakes are manual, not power. I plan on either replacing the cab on my truck or seeing how much it would cost for body work to fix the existing cab. Thanks in advance.