Hello old timer! I'm no expert, but I'm going to take a stab at it. I think it's a 1975 brownie 18" model. Your saying its a 22" though. The flat handle on the bowl is throwing me off. I thought the 22" had round handles and 18"'s were flat.
Also, the lid vent stamp says "bar-b-q-kettle" which changed to "Weber" in 76'.
The bowl tabs on the bottom are large and have 2 tabs per vent which was changed in 75' from the small singular tab.
Finally, your wheels look to be the plastic ones, but without the Weber logo cut into it. They started that in 77'.
Only way I know how to fix the bowl tabs is to use a soft mallet and a screw driver. Or do they not move? In that case try good ol' wd40 or pb blaster and let it soak then gingerly tap, budge, manipulate them until free. I have a Fleetwood 26" that I had to spray and work back and forth forever! Hopefully yours aren't too far gone though. If they do move you can manipulate the tabs back down with the a flat head and re shape the vent by softly hammering the vent outer area.
Get a couple more pics, and everything I've mentioned here is posted on the age guide provided in the forum. Only thing I wonder about is that flat bowl handle.
Hey glad to meet ya!
Hey, just an update. I just saw you said the vents were three holes. That's an 18" for sure. 22's had 4 holes.
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