I don't believe the Contra G was introduced until 1964. I could be wrong but, in 1959 the debut of the "regular" Contra was a pretty big deal.
Yes, I think you are correct! I referred to information on CSCC first. It is listed there with 1959 as the year of introduction.
There is a site in Germany that shows an easier to follow list of the major Stihl models: motorsaegen-portal.de - Das Motorsgen-Portal
Here the years of production are as follows:
- Contra: 1959 - 1968
- Contra S: 1964 - 1967
- Contra G: 1964 - 1969
- Contra GS: 1964 - 1969
And the introduction years of the 070/090:
- 070: 1968
- 090: 1968
- 090G: 1969
- 090 S1: 1968
- 090 S2: 1968
These dates seem to be more to the point.
Interesting is, that the S1 and S2 (stone cutter versions) of the 090 were introduced one year earlier than the "regular" 090G and the Contra G and GS were produced during that year...