For me, weathering, specifically engines and rolling stock, is what separates the toy train modeler from the hi-rail or scale modeler. Some guys fuss about the center rail and they say THAT makes it a toy train. Maybe so. But taking a layout as a whole, the biggest differentiator of the toy train look from the scale or hi-rail look is weathering. So I think charging the scale modeler for weathering service is valid. How much you can charge is another question. You'd have to experiment with weathered versus new look auctions on eBay.....or just advertise and see what the response is like. Lionel sold a factory-weathered N&W 611 J engine. And I suppose they also sold the non-weathered version. Was there a price difference between the two? I don't know my Lionel well enough to know.
Good luck!
Don Merz
