How old are CENTER FLOW HOPPER CORNING HO SCALE with plastic wheels

[waxsaw]

How old are the CENTER FLOW HOPPER CORNING HO SCALE with plastic wheels? I see the current model 17545 has metal wheels.
I'm hoping to determine what to value the older ones in comparison to the prices I see for the newer. Also quality wise are the older much lighter weight and less sturdy?

[Conrail Quality]

At least 10+ years old. As for value, they are worth a few dollars at most since they are much poorer quality than modern rolling stock (lighter weight, plastic wheels, horn-hook couplers, etc.). HO scale is not Lionel: older is rarely better.

Timothy