Maybe, but it does matter where the rotor arm is pointing.... Which is why when you install the crank, you ensure the rotor is pointing TDC, for Rod #1.
You can set the dissy drive later by the the position of the end of the crank and the marks on the case
^^ what they all said You can do it later with the rod at max throw and poke the push rods into the cam followers they should give you all the indicators require for TDC and 1 firing