Yes, dark Westy tops get realy hot in the summer sun.
Painting solution:  Paint just the top of the top white (mask off about
1/2 inch in from the edge) to keep the original paint scheme.  Other
alternatives include heat reflecting space blankets, etc.  One local
owner had bad results using KoolCoat RV reflective roof paint.
Apparently ruber based, it ended up pealing off in one large sheet!