We used some of the two-part epoxy putty to build up a missing piece in the back of ours (probably in the same place your's is broken). I think the stuff is called PC-7 and comes in a set of red and black cans. Mix it up and put a small glob where you need it. It is very sticky for a while, but in an hour or so, it will still be pliable but not sticky to the touch. That is when you can shape it more closely to your needs. In 4 or 5 hours you can sand it to the exact contour and then you might scratch some grain into it with a small nail. We also backed up some of the cracked areas that we mended with super glue using the same putty. By the way, the hole in the back of a 70 console is for the seat belt buckles, the ashtray was on later consoles. Good luck with your repairs.