According with the shop manual online the door trim is installed even with the front edge of the door. Does the trim hit the door when the door is completely open or before?
I have seen several 50 and 51 Belairs that have a dent in the door trim from hitting the fender edge when the door opens too far. I have a 51 Belair with all the trim off for sandblasting and there isn't much clearance between the door and fender when the door is opened.
I wonder if the door check is allowing the door to open too far? I don't know if you have a 1949-1953 passanger car shop manual, so here is a link to Keith Hardy's website.
1949 - 53 Chevrolet Passanger shop manual It may be helpful to read the complete chapter on
Body 1.1I hope you find the information needed.