Buying a multi fam home but listed as a SFH

[Will Amey]

Hi I'm in the process in buying a Multi-Fam property but owner has it listed as a SFH. The land is already zoned for multi fam and the home is already build as a duplex. Reason for being listed as a SFH is because permits have not been submitted for approval. My question is what is the process and estimated cost to get the permits myself if inspection goes well? For extra info the home is in Riverside County, California