I happen to be flying from SFO to Newark on Christmas day with a stopover in Detroit. However, my flight from Detroit to Newark has been downgraded from a DC-95 to a CRJ-900

My family will be flying with around 4 checked bags. The flight from SFO to Detroit is a 73H and we have no problem checking bags onto THAT flight, but are normal checked bags [50 lb weight limit] allowed on Delta Connection? If so, will it be gate checked? I'm confused