As i see it, it's not PO, but P0 (not P"O" but PZero1038)
so when i typed it on goggle this appears;
P01038
FAA-approved replacement for OEM P/N S4-4500160 ( Plane part , actuator of cargo door)
Description: Sleeve Assembly, Locking
For use in Line Replaceable Unit: Cargo Door Actuator
Just a simple metal and cannot be associated with polonium, Polonium is a chemical element with symbol Po not P0 as in P zero.
Polonium,
It has atomic number 84, discovered in 1898 by Marie Curie and Pierre Curie. A rare and highly radioactive element with no stable isotopes, polonium is chemically similar to bismuth and tellurium, and it occurs in uranium ores. Applications of polonium are few. They include heaters in space probes, antistatic devices, and sources of neutrons and alpha particles. Because of its position in the periodic table, polonium is sometimes classified as a metalloid.[3] Other sources say that on the basis of its properties and behavior, it is "unambiguously a metal"