Maybe this will help or maybe it won't.
John Maxwell, now deceased, developed quite a collection of (redrawn) D&RGW drawings that are now handled (I believe)by his son. Maxwell used to have a web site with available drawing lists.
Now whether there exists in his collection a drawing, and 'IF', on that drawing, a pattern number (if D&RGW) or manufacturer with part number is shown, is a very long shot.
There is probably nothing at Colo. RR Museum but they also might be worth a try.
Maybe someone else has a suggestion.
Good luck,
Chris