Thanks for your response, although I find it hard to fully accept. Mainly because both RailKing 2-8-0 engines I own have removable die-cast sand and steam domes. Even the 4-8-2 I'm working on (Lionel) has the die-cast steam dome as a separate piece, although I had to cut off the sand dome.
But I will take you suggestion and continue looking for older Williams brass.