Polyp is a term that is used to refer to usually benign or pre-malignant growths of epithelial linings (such as the linings of the intestinal and genitourinary tracts). Therefore, the liver itself would not develop any polyps. On the other hand, the bile ducts coming out of the liver and inside the liver may develop local growths of their epithelial linings that would essentially be polyps.
That said, certain liver growths could extend from the liver surface in a "polypoid fashion," for example larger hemangiomas and potentially other growths. However, despite their "polypoid" appearances, these would really not be liver polyps.
Possibly, you are referring to gallbladder polyps that are anatomically close to the liver, and it is indeed possible to get gallbladder polyps.
I hope that this can help to answer your question. All the best.
I really don't know, I did a google search and could not find any info. Maybe the library will have books that can help, or, the doctor's nurse.
Sorry, I wish I could be of more help.