I got my other bb question answered , just need help with 1 more

I have a new frame, and want to put on the headset today

usually on a new frame I haul the bike up to lbs and have them face and prep for the installation

is it absolutely necessary to face the headtube

can I just go ahead and press the headset on without prep

anything bad going to happen with the frame if I just go ahead install

thank s