Yes. The bits that stick out go into the cam chain wheel - which of course i forgot to mention when describing the process!!
So, cam halves (with key fully in one side) into head with cam chain wheel and its slot aligned with the key and three studs in place so the key and protruding cam end shafts fit into place, tap together and fit nuts and washers, tighten, job done. They go together very easily. Don't worry if it's not perfectly centered - you can tap it across to find centre and the cam end covers will get it spot on once fitted anyway.
When you had the nearing pressed on is when you should have had the cam flanges pressed on, with the key in one side. Do you have easy access to that press and its operator?