The LG G4 was released in the US in early June 2015, as always focusing on high-end specifications and a refined fashion sense that makes it stand out in the premium smartphone market. Each version of the phone will have a different model number based on if it is sold by a carrier or unlocked (US or International). Some LG G4's are known to have bootloop problems.
If the previous owner wiped it via recovery, you will need to contact him to login in to the phone. Once he does, you then go to Settings --> Backup and Reset, and reset from there. That will permanently remove the google lock.