Replace tranny mount

I need to replace the trans mount on my 70 Duster. It appears to have a lip holding the old one in place. I don't see any way to get the old one out and new one in other than cutting that lip off, to heavy to bend it. Any problems if I cut it?

Also, anyone use the poly mounts for the transmission? Are the worth double the price of rubber?

Sorry about the sideways picture, tried it three times and iPhone won't let me upload a rotated pic.