I believe that from the factory the trans was not even painted on the 1950's and 60's Ford cars and trucks. They were bare cast iron that’s how I remember many of that era of Fords and also the new 56 F-100 (with the 223 and 3 speed) that my dad ordered.
Many times when the motors or trans were rebuilt and unless you could insist, that you wanted it original or a special color the different re-builders would just paint them with a bulk paint color that they used on everything. The old junkyards would do a so-called rebuild with replacement of the damaged part or parts with a good used part, clean it some and then paint it. Slang name was a junk yard or spay can rebuild. Pro trans re-builders would did a better job by replacing all the wearable parts and they cleaned them excellent so the paint job also looked better.
There is a paint that’s been available for quite a few years that gives the look of new cast iron I think maybe its called cast blast. My 54 still has original paint and decal on the air cleaner I know that the engine has been rebuilt at least once so the block and head color may be wrong. Good luck with your 54.