They are for different motors, but as Wayne states, you can modify it to suit.
Your switch with the knife connector is for the earlier models, the 25/30hp versions. They did not have an inline vacuum cut out like the 35hp you are working on wired to the mercury switch. The lead from the mercury switch simply had a knife connector, which attached to the lead coming from the push button starter switch, to supply the ground for the push button starter to activate. Prevented started at high throttle settings.
As you can see on his 35hp, they added an inline cut out switch, so the lead has an eyelet to connect to the post on the cut out switch. Different set up, same principles.
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