The absence of a date code on the lid vent suggests that your kettle is at least 30 years old. I don't know when Weber moved from Arlington Heights to Palatine, but perhaps someone else in the community does, and can narrow the possibilities further.
As for replacing the wooden handle(s), a woman at Weber CS told me a few months back that Weber ran out of the wooden handles about a year and a half ago, and has no plans to replenish its supply.
If you do replace a wheel, you may want to move the legs into different sockets so that you will be able to roll the kettle by pulling on a side handle.
Nice find.