Correct. With the shaft retracted the wastegate is closed.

The vacuum actuator (original) keeps the valve closed (under vacuum) to supply boost. The pressure driven actuator (new unit) is closed by default (always supplies boost) except when it receives positive pressure.

The difference between the two is that if the original unit failed the wastegate defaults to being opened while after the swap if the unit fails the wastegate is always closed.

While Dave's original post advises to cut the shaft and add some more threads (Harbor Freight has the dye at a low cost) it has been discussed that it may not be necessary.

The new unit is installed in exactly the same manner as the original one.

You'll also want to clean out tour over pressure switch that goes from the intake manifold to the ALDA.