Static Meshes not showing up in build after attempting Merge into instanced static meshes

Hi everyone
Im working on a medium sized map and wanted to convert a number of my simliar buildings to ISM (instanced static mesh). I did this using select simliar merge → batch

problem is now since i did not notice a boost in performance, i deleted the merged actor and simply unhid all of the existing actors that the process had hidden.

i also made sure to uncheck hidden in game

problem is now in the editor things are fine but when i try to package my game unless i dont delete and replace my old static mesh actors, they do not show up in the build

is there a setting that the batch process has flicked on that i cannot find ?
thank you for the help