Naa, just put a plastic cup, or something, over the control knob to keep the water out. Should be fine.
This is what I use on my # 1 that I got a lowe's and I leave it in all the time, its heat deflectors that you use in your home, it's got magnets on it but it doesn't stick to the stainless steel so I just put some duct tape on the sides and it's been on there for 2 weeks. cost was under 3.00 I can still turn the nob for temp.
I always thought these were water resistant/proof smokers? I've smoked in the rain and snow without protecting my knob/light/hole/etc and never noticed issue other than needing to wipe water off the top after the rain. Is covering this knob necessary or is everyone here just taking extra precautions? I mostly use my HeaterMeter PID to cook these days but I have a bypass switch so I can go back to the analog controller at will.