I found a photo advertisement of a "1-owner hardly used" 1982 and it had the newer-style font. I also found pics of 2 1981s that had the older-style font. So 1982 looks like when the graphics changeover occurred.
Regarding serial numbers, mine is 17594. I found info from Bob Jackson that 17311 was built in September 1983. So I'm thinking mine was built late 1983 or early 1984.