Legal Question in Criminal Law in Minnesota

As a practical matter, yes. Because pre-trial motions requesting suppression of prosecution evidence and dismissal of charges, and the like, must be reduced to writing, served on the prosecutor, and filed with the court - well prior to a Contested Omnibus Hearing. Sometimes I verbally request the court set a Contested Omnibus Hearing, but I follow that up with a written motion. So, though it may be possible to request a Contested Omnibus Hearing verbally, best practice is to serve and file defense motions for that hearing in writing. In cases not involving a felony or gross misdemeanor charge, the court rules, courts and lawyers sometimes proceed less formally. But written motions are normally better, even in those cases.