4 weapons in total will be missing, and can be purchased in a bundle for $5.99. They are all available for use in pre-made loadouts, but must be purchased to be used in custom loadouts. None of the four are game-breaking, and are given the proper loadout cost as to not become unbalanced. You can do absolutely fine in the mp without ever touching any of them.
edit: Can we add to the op that dlc weapons, hats, and skills are not included with TLOU:R unless you have already purchased them individually or as part of the season pass for the ps3 version. TLOU:R includes Grounded Mode, Left Behind, and the dlc mp maps, but not the weapons, hats and skills.