Entirely content/viewpoint-based restrictions would likely implicate the 1st Amendment. However, if the restrictions are focused only on the time/place/manner of speech and apply equally to all, then they would probably be allowed. This is a fact-specific analysis, so without the facts, it can't be said. Good luck.
I have been licensed to practice in the State of Oregon since 1990. I am not offering legal advice regarding your question, only general information regarding the law. You are not my client nor am I your attorney unless we sign a retainer agreement.