Psilocybin cannot be a freebase. It is a zwitterion.
A zwitterion (first part pronounced "tsvitter", from German "Zwitter" — "hybrid," "hermaphrodite") is a chemical compound that is electrically neutral but carries formal positive and negative charges on different atoms.[1] Zwitterions are polar and usually have a high solubility in water and a poor solubility in most organic solvents.
Some drugs such as methamphetamine, MDMA, and mescaline are strong-smelling, corrosive oily yellow liquids when in base form and so are rarely ingested as bases, instead almost always being encountered as the hydrochloride or sulfate salts.
Ever read your cold medicine packages. Ever see HCL after a drug? Like pseudophedrine HCL. HCL is the form you would ingest, it is the acid form of a drug.
Freebase would be the base form of a drug and is usually the form it has to be in to be active when inhaled through the lungs.
Zwitterions are neutral meaning they are neither a base nor an acid.