EIFS over open framing

This house had (PI) EIFS over open framing. The house was next to a golf course and had many divets. The client wanted to know about the cost of putting a more golf ball resistant siding on. In the attic I noticed that there is no substrate, plywood, OSB, etc. My gut feeling is that to install new siding the EIFS will need to be removed and a substrate installed which would be quite expensive. Am I right about this? Opinions? Check out the golf ball embedded in the EIFS.

only golf ball proof product I know of is concrete