Did the stone have to be removed before Jesus exited the grave?

Matthew 28:1-2: After the Sabbath, at dawn on the first day of the week, Mary Magdalene and the other Mary went to look at the tomb. There was a violent earthquake, for an angel of the Lord came down from heaven and, going to the tomb, rolled back the stone and sat on it.

Mark 16:2-5: Very early on the first day of the week, just after sunrise, they were on their way to the tomb and they asked each other, "Who will roll the stone away from the entrance of the tomb?" But when they looked up, they saw that the stone, which was very large, had been rolled away. As they entered the tomb, they saw a young man dressed in a white robe sitting on the right side, and they were alarmed.

No, not necessarily. Jesus in his new resurrection body (1 Cor. 15:35-49) could go through walls and doors (John 20:19, 26; compare Acts 12:10). So, I do not feel a stone was any kind of obstacle that he could not go through. The stone could have been rolled back strictly as evidence that he had risen (and rise he did, Acts 2:32; 1 Cor. 15:1-4), not that it had to be moved so he could rise. This would also be consistent with:

Matthew 28:5-10 The angel said to the women, "Do not be afraid, for I know that you are looking for Jesus, who was crucified. He is not here; he has risen, just as he said. Come and see the place where he lay. Then go quickly and tell his disciples: 'He has risen from the dead and is going ahead of you into Galilee. There you will see him.' Now I have told you." So the women hurried away from the tomb, afraid yet filled with joy, and ran to tell his disciples. Suddenly Jesus met them. "Greetings," he said. They came to him, clasped his feet and worshiped him. Then Jesus said to them, "Do not be afraid. Go and tell my brothers to go to Galilee; there they will see me."

So, in essence we could say that stone was rolled away so that we could look into the tomb and see that it was forever empty! He has risen. He has risen indeed!

This said, I do believe Jesus exited the grave by means of the stone being removed. First, the text does not say otherwise (why, if such a great miracle as this took place?). Second, Jesus had said earlier, "For as Jonah was three days and three nights in the belly of a huge fish, so the Son of Man will be three days and three nights in the heart of the earth" (Matt. 12:40). Of course, although the correlation of these two events is not meant to be one-to-one, Jonah was "delivered" from the whale: "'You brought my life up from the pit, O Lord my God... Salvation comes from the Lord.' And the Lord commanded the fish, and it vomited Jonah onto dry land" (Jonah 2:6, 9-10). In a similar way, I believe God commanded the angel to remove the stone and "deliver" Jesus up from the pit.