Broken Mast Base

I was stepping the mast on my 1986 hobie 16 today and casting of the mast base broke away from the two rivets. I looked on a previous post and ordered a new base from a Murrys link (thanks), but they are not 100% sure that it will fit on an older model Hobie (he said something about the rake). Has anyone had any experience with this or have any broken mast base alternatives?