Yes, I'm afraid that is the case.
Then you should get the form Report of Lost or Stolen Motor Vehicle Items MV-78B from a police agency. Also get form MV-78B if your items were lost because of a crime. Your items will be replaced at no fee if form MV-78B shows the items were lost because of a crime.
Can I also apply by phone?
Unfortunately, you can't apply to replace IRP registration items by phone.