Actually, repowered my STBD engine with a Mercruiser Horizon FWC last season. Converted the PORT motor to FWC at same time. I want to replace the original port engine black Mercruiser engine cover with a silver Horizon cover so that they match. Been hunting online everywhere.
Maybe someone with a single engine boat would be willing to swap with you. Someone may take the silver cover from you and give you back their black cover in return. Then you would have two black covers. Or, vice versa and then you would have two silver covers. Hey, it's worth a try.