You will get peeks at the joeys during the last couple weeks they are in pouch. She may even let them hang completely out of the pouch for grooming.
They are considered Out Of Pouch when the have detached from the nipple. If you can see their full face or if mom can move away from them - then they are OOP.
Do not try to handle them if they are nursing with their faces or heads in the pouch. They may not have actually detached, and if separated from the nipple too young, they may not be able to reattach to continue their development.