Of course.
Phosphate coatings are porous and absorb oil and lubrication well by design. These are current Mil-Spec by the U.S. Military. When used in conjunction with quality external oils, a phosphate coating will protect the external of the BCG from corrosion. But, you must lubricate phosphate finishes regularly to give that protection.
NP3 is an Electroless Nickel coating with embedded TEFLON. The TEFLON is bonded to the particles of Nickel at the molecular level providing self lubrication throughout the entire coating. The Nickel in this finish provides corrosion and abrasion resistance. NP3 BCGs require less lubrication and they typically withstand heat and friction better than a standard phosphate or nitride-coated BCG. Because NP3 is chrome-like, it wipes off and cleans easily, often requiring no solvents or harsh chemicals.