While I don't do mono's, never seen a mount like that. Believe it to be home made. DON'T put the screws thru the hull..

Most mounts have basicly what you have, but don't use the outter bracket. Instead, there should be ply wood rails to mount the engine mount to. Measure the distance from the rubber mount to rubber mount, outside that is. Then glass in two 3/8" ply that distance apart. Might be a good idea to figure out where the mount holes will need to be drilled in the wood rails before glassing in.

Certain others will join in...