Putting a 318 together and something seems wrong here (see pic)

Did the rear of the thrush plate have the oil groove in it? All the ones ive had appart, even with the chain oil tab, all 4 bolt holes still lined up. Witch is what led me to believe it may be on backwards. Even though it had bolt marks on the face whos to say someone hadnt changed the cam at some point an put it on backwards themselves.