The weather controller class also has this issue, it seems like it's intended to be an extendable/modded class but it reports the same thing, engine class cannot be modded. This is in the weather.c script file. Not sure if it's intended or not, just reporting it.

Because you don't have to, class Magazine is inherited from class ItemBase which can be modded

Magazine myMagazine = ...
myMagazine.DoSomething():

..

modded class ItemBase
{
     void DoSomething()
     {
     }
}

@Masspwnaged @Niphoria @Baconproteter @AussieCleetus

Actually, we should have the possibility to do modded class of magazine for overriding some functions