Hi Eddie, The dowel is not absolutely necessary, but it should be there. Why not call John and ask him to get one out of another block, you will probably want to pick it up since you're getting ready to install the new engine. If you had more time he could mail it, of course. He's a great guy, probably didn't even notice it was missing. God bless you and your family.
Good luck, Nick Brann, K.C., MO