Boiler,
Some of the Premier models that I own, have a more refined, realistic appearance.
For example, my BNSF AC6000CW - the sun shades are different from all of my other modern GE models, the ribbed long hood filters aren't as crisp and the front door is molded-in. Even though my 6000 was made just a few years ago, it's shell appears to be made from older tooling. The Hi-Ad trucks are the same though, as my other current/modern GE's.
My NS SD80MAC has two opening cab doors, one at the front of the cab and the other, at the rear, behind the engineer's seat. My CP SD9043MAC's rear cab door is the only one that opens... the front door is molded-in. The truck placement/layout doesn't seem to be as accurate, as my SD70ACe's and SD70M-2.
My BNSF SD70MAC's truck layout/placement looks off, as well. I'm also wondering if the shell is MTH's own creation, their own tooling, or did they just acquire the tooling from another manufacturer? The molded-in detail, on the shell, just doesn't appear to be as good, as some of my other modern Premier models.
I'm thinking... these models are made using older tooling...
Rick