Looking at your kettle, the metal bowl handles on the 18.5's were always smaller and more square shaped than the metal handles on the 22.5. They were this way through 1980. Wood bowl handles came out in 1981. The lid vent points to 1971-1975, based on engraving, patent number, and the small rounded tab. The early plastic wheels, that appear to have plastic treads puts it around '73-'75. I have a red 18.5 (see The Easterner) with thumbscrews in the sockets, no patent pending/number and metal wheels with rubber treads and a wood lid handle. It also says Arlington Heights, my 18.5 ranges from 1964-1967-68.
One touch came out in 1983. Daisy wheel kettles remained available in the U.S. new through 1999. I've geeked out on researching the plethora of variations to the kettles through the decades. From turn tab shape and size to wheel styles, to lid shape to vent engraving.