The chassis in the Webstacars packet looks similar to the photo Joel posted in 2013, although there are differences in the drop arm and it's not clear if the plating is the same. The Webstacars one in the photos appears to be brass coloured, although it's difficult to be certain without looking at the actual chassis.
After all those years, I suppose there's a very remote chance of finding somebody who knows more about where Webstacars sourced their products.