Yes, have a lawyer, because whether this is a misdemeanor charge or otherwise, you need your rights protected and your options explained to you any time you are threatened with a matter that can cost you your liberty. The realities are that you won't go to jail for this, but the statute allows for it. You have a Constitutional right to a lawyer under those circumstances. Take advantage of it.
You do not want to take advice from the police when you are a criminal
defendant. You do not even want to speak to the police when you are a criminal defendant. Anything you say to them, or to anyone other than your lawyer (and that includes the judge) can be used against you. On the other hand, what your lawyer will say cannot.
As for the knife, in order to prosecute you for this offense, the DA will have to show that there is a knife. And that means that the DA will get to see the knife when the police turn over their paperwork to the DA. If the knife is not a switchblade, the DA will charge the lower level offense, regardless of what the police officer wrote on the ticket. If the DA thinks it's a switchblade, you and your lawyer will have a right to see the knife and challenge the evidence at a pre trial
hearing if you want to fight the case.