It absolutely would have been not only Matzoh but a special type of Matzoh kosher for Passover. We know this because the room that they ate in had already been prepaired for the passover
Luk 22:7 Then came the day of Chag HaMatzah on which it was necessary for the Pesach to be sacrificed.
Luk 22:8 And He sent Petros and Yochanan, saying, "Go and prepare the Pesach for us, that we may eat it."
Part of the preperation was and still is the cleaning of all kushrach (leven) from the place where the passover meal would be eaten. Thus in no way would they have brought into the building leven (raised bread specifically)
IN fact it would have been a very special matzoh that was carefully prepaired so as to drive all mosture from it To do so renders this bread both Pierced and Striped.
If you look at the extremely Jewish part of this last supper the whole story really takes on a whole new significance.
I really urge all of you that ever have an opportunity to do so to attend a Messianic Seder you will learn A LOT!
Blessings
Pastor George (The Messianic Mennonite!)