2006 Dodge Caravan fuel injector

Removed fuel rail and injectors (Bosch) during a head gasket replacement. The plastic seats on two injectors going into the lower intake manifold broke. It appears the seats are not available, only o-rings. Do I need to replace the injectors, or can I use old ones without the plastic seats? Been told the seats were there for a reason so should replace, do you agree or know where I can find the seats?