To be more specific. As per the Piper Cherokee Parts Catalog, part 753582, 2009 pub date, there is no specific part number for a landing light. Nor for position lights. Nor for tail beacon. There's a specific part number for the retainer ring for the landing light, tho. (Ref Figure 56).
But there is a specific part number for the air filter. But not for the oil filter.
There is no specific part number for the little lights that go behind the panel overlay, either. But there's a part number for the overlay, and the dimmer switch for the panel lights. I find it difficult to believe that someone at Piper, or even at GE, ran any type of test to verify the 99 cent GE53 bulbs would satify the FAR specs. The only spec I can find, other than physical dimension, 12-14.4v and 13 lumen. Looking at various suppliers, the listed wattage is either 0.12w, 1.7w or 2.0 w. Very odd. By the way, as a trivia note, "53" is the ANSI identifier, not the name GE gave it.