oil jet question?

I had my head rebuilt on my 88 Si. The manuel said to make sure the oil jet is positioned right before re-installing the head. I was just wondering if it is really necessary to replace the O-ring on this oil jet? I have to wait til tomorrow to go to the parts house to get one. I couldn't do anything else on the car cuz I can't put the head back on until I replace the O-ring. Let me know. I'm going to replace it anyway, i'm just wondering if it was worth it to stop working a few hours early today just for this damn O-ring. Thanks

If you took the time to pull the head and rebuild it... replace all gaskets and "O" rings. Murphy's Law says it will fail and ruin your day at the worst possible moment.

I have an 88 lude Si and just turned over 250K miles and still running strong... a few little glitches here and there, but then again older cars need the attention.