Howdy, LJames!
I re-read your post but am still confused. (Happens more and more as I get older and older!) You say you bought the WSM on Friday and that on Monday you have digestive track problems. When did you cook? More specifically, how long after you ate the cooked meat did you begin to show symptoms?
As others pointed out, you do have to season all cooking apparatus - especially the surfaces that contact food. In fact, most experts recommend that you raise a high heat before placing anything on the grill and let the grill get very hot then clean it with a metal bristle brush then wipe it down with paper towels or a rag soaked in vegetable oil (the last bit to keep food from sticking). The high heat will kill virtually all the bacteria you are likely to encounter. It is always possible that the food was contaminated in preparation, but that rarely happens in the normal household kitchen with beef. If, however, you had prepared poultry without disinfecting all surfaces, utensils and even your sink - EVERYTHING touched or brought near the poultry - you might easily get cross-contamination. I keep a spray bottle of Clorox under the sink for this purpose and always disinfect as soon as any poultry is taken away from the food prep area.
Having said all that, it is just possible that there was an unrelated cause of the stomach upset. Here's my tale.
Just over a year ago, I had a sudden onset of fever just minutes of eating a dinner of homemade gazpacho and garden salad. I got the fever down with rubbing alcohol and frozen gel packs but it returned with vengeance the next day. I was rushed through the ER and into surgery to open the site of my artificial knee. It seems I had picked up an infection from a common bacterium and it **** near killed me. I was blaming the cold soup and garden salad but the doctors assured me that the infection could not possibly have grown that rapidly. The artificial joint represents a slightly debilitated immune system which was attacked by an otherwise harmless every-day bacterium. I spent a month in the hospital and 6 more weeks taking intravenous antibiotic through a central line and continue to take twice-daily antibiotics.
The moral of the story is that almost any bacteria can kill you if your immune system is compromised. Most problems from ingestion require 4-12 hours to develop symptoms that are noticeable, according to my medicos. I have become compulsive and obsessive about cleanliness in the kitchen and care with food prep.