The Weber really doesn't need to be seasoned. I would wash the grate first to get any manufacturing residue of it. I'm not sure about the Masterbuilt. Since it is a LP smoker I don't know if you need to season it.
Team: Pyle's BBQ; Good-One "Trail Boss" 60T; Homemade rig; 22" Weber Kettle w/rotisserie ring; Big A$$ Rotisserie; BGE-Small; Weber Kettle Gold, Weber OTS, New Braunfels offset smoker.
Saddles BBQ Bistro