From our perspective there is no event horizon since the collapsing star has not reached the black hole state. In fact it takes infinite amount of time from the point of view of an external observer for the event horizon to form.
In almost all situations it does matter as the collapsing star will behave as it is a black hole. But for the merge of black holes it is significant as it allows to release energy as there is no event horizon.
In almost all situations it does matter as the collapsing star will behave as it is a black hole. But for the merge of black holes it is significant as it allows to release energy as there is no event horizon.