From Newmar.
I'm not sure what has changed at the border, I've only heard this happen a few times in over twenty years hear at Newmar, and you're my second email today with this question.
Newmar Corporation is only required to provide the sticker behind the driver's seat which is generally always accepted when crossing the border. However, Spartan Chassis does stamp the last five digits of the VIN four times on the frame rails. Once on the main chassis frame rail behind the steering axle tires, passenger and drivers side, and the same behind the drive axle tires. If you need further assistance in locating them, you can reach Spartan at 800-543-4277, for better assistance.
Waiting on a response from Spartan