Charged with 4462.5 vc in San Diego, what to expect?

If you take proof that you had insurance to court, that charge will be dismissed for a $25 administrative fee. Your bigger problem is the false tags, since you deliberately and deceptively used tags from a registered vehicle on another vehicle. I doubt that jail would be imposed on that, but you should be represented by counsel on any misdemeanor offense. If you cannot afford an attorney, one will be appointed for you. The scheduled fine for 4462.5 is about $680, so you are probably going to be out some cash in any case.