Your best bet is to search/read your municipal codes. Usually keywords such as "park", "firearm", "gun", "pistol", "griffith" should turn up information concerning carrying in Griffith. Any laws which outright prohibit the carrying in the park are unenforceable though as the state laws supersede local ones. There are state laws prohibiting you from entering publicly owned buildings as well as state parks.
Redondo PD demonstrated last weekend exactly how a PD can enforce illegal laws/municipal codes.
This is factually incorrect. Redondo PD demonstrated how a PD can intimidate the public into following laws which are illegal. Nobody was arrested, people were just intimidated into behaving the way the city wished people to behave.
I used the word "unenforceable" previously because while police officers can arrest you for municipal codes, you have a incredibly strong defense since the codes conflict with state law, which makes them void. I don't view the ability of the police to arrest somebody as enforcing the law. I view the legal system in its totality as enforcing the law, and I do not believe a municipal code such as Redondo's would be enforceable.
Are you available to come test this assumption? It'd be great to have a test subject that is willing to do this.
I'm sure we could find people willing to cover your travel expenses.