Buick Repair Questions? Ask a Mechanic for Answers ASAP
It really doesn't matter. The pressurized oil will flow around the groove of the lifter and into the hole not matter which way the hole is pointing.
One thing you might want to be careful of is not to over torque the rocker arms when you re-assemble. The threads strip out very easily and its a huge pain to have to repair the threads once they pull out.