Can a PL 170.05 be dismissed on grounds of not knowing plates of a car belonged to a different car?

The short answer to your question is yes, it could potentially be dismissed based upon those grounds. However, getting to a dismissal can be a difficult road. There are a few different ways that you can get there - 1) Your attorney can negotiate with the district attorney, provide them with this information, provide them with proof that the vehicle belonged to a friend and that you could not have possibly known that the plates were forged. 2) There may be some sort of deficiency in the criminal court complaint that could lead to a dismissal. 3) If all else fails, you may be able to get an acquittal at trial, if the Prosecution is unable to prove beyond a reasonable doubt that you, with the intent to defraud, deceive, or injure another, falsely made, completed, or altered the plates.    With all that being said, your attorney should be in contact with the District Attorney's Office, informing them of this information and negotiating a plea deal on your behalf. It's very unlikely that a case like yours, with your background (no prior arrests and 18 yo) would end up with any type of criminal disposition on a misdemeanor forgery case. However, it may be a situation where the District Attorney isn't willing to outright dismiss the case, but instead would offer you some sort of non-criminal disposition, such as an adjournment in contemplation of dismissal with some community service, or a disorderly conduct violation with a fine.