So I looked through all of my dashes and have five, four are canadian and one is american, All of the Canadian ones do not have the scallops on the bottom and are pot metal, none of my dashed are aluminum, It would appear that the ones that are not scalloped are Canadian,. and by that I mean that they are the flat variety, So this is not a way to tell if aluminum or not, maybe other Canadians can chime in and verify the style. may be that the Canadian version is the same casting mold style of the aluminum one, just more wood for the fire!!! I just think its interesting if nothing else!