TITLE STATES 1969 SERIAL NUMBER SHOWS IT AS A 1960

So are the serial number charts right, I checked a couple of different places and they showed the same thing listed the motor as a 1960. Thing is I have 2 different motors with this problem. The other is a Mercury 7.5 Title states 1973, but by serial number and decal color it shows 80-81. Am I looking at the charts right, if so do alot of the used motors you buy have this problem.

Evinrude Lark II 40 HP
Mdl# 35520
Ser# 20774

Mercury 7.5 HP
Ser# 5617846

I looked up the ser number of your 7.5hp and the chart said 1981. When I bought an evinrude I had to search the numbers to find the year and so far I'm sure the chart was right because I've look up on youtube and found the same outboards that I have with the same year.

When was the title issued?

It wouldn't be a 80-81 if it was issued in 73 and original. I'm assuming the serial numbers match the titles?