The 14-piece stainless steel fender trim was available as part of RPO 390B, installed at the factory on Panel trucks. These "bright metal moldings for front and rear fenders)" were not available in an RPO for Canopy Express or Carryall Suburban trucks. And, it looks like this option was not an RPO for Panels between late 1952 (maybe late 1951) through 1953.
No one has posted information about an installation manual or hole-drilling templates. Presumably, someone could have bought the stainless trim as parts from GM (but they were not listed as an accessory).
Here is an illustration, showing the placement of these moldings. 
