Those familiar with these engines will know that, more often than not, the oil pressure indication does not rise out of the "Low Oil Press zone" until after engine has started/50 %. After all, that is the time to be concerned, when the engine is actually running and self sustaining.
As long as the pressure is rising during the start sequence there is no cause for concern. To the "Old school" among us, Me, the observation during the start sequence goes; Start valve open - N2 - Ignition - Fuel flow- Light off - N1 - Oil pressure.
So, to answer your question, No you do not have to but not a bad idea. At least you are ready for a warning if the pressure does no finally come up.