If I recall correctly, the morning after the dance, Marty is seen with one button on the trapdoor of his long johns unbuttoned.
Revealing one of his butt cheeks.
I have one, I was told Pietta parts when I was looking to replace grip frame screws.
Short answer is Pietta.
I otherwise, have had no issues with said weapon.
Depending on the age of the weapon and when Pietta and Uberti started sharing common parts.....could be either.