10 micron,
Check out the part numbers
on this link - the Master Parts Catalog. Post the part numbers here and I will compare the Chevrolet part numbers to GMC part numbers for the same year (I have bought those brake parts for my 54/55 GMC 2-ton COE).
I fully understand your question and your comment about being careful and being new to big trucks (a new world for us small truck people). Part numbers are not usually in a Shop Manual. Nonetheless, a Shop Manual will tell you what sizes of trucks have matching brake systems/parts (but not give part numbers).
I was very fortunate to be given GMC part numbers for my truck by big-truck people on the oldGMCtruck.com website.
Good luck,
Tim
