I cannot say for sure but it should not make a difference as this is a non polarized electrolytic capacitor.

--I on the wiring diagram is the positive goes to the blue (board)

--) is the negative goes to the motor's start winding

Not sure why they show the above on the wiring diagram and if there are no markings on the connectors other than 1 and 2 then it is immaterial.

What was the original problem?
How was the capacitor tested?

The only decent way to test a capacitor is with a capacitance tester. A mutimeter does not do a good job of this as it cannot test it at it's operating voltage and often they leak/break down at higher voltage. The multimeter will only tell you if it is a dead short, a full open and that it will take a low voltage charge.