If the article is accessible from the Category Blog
menu item, i.e. it appears in articles listed in the blog it will inherit the module positions of the Blog
menu item. Thats how stock standard Joomla generally works. At least I think that's the way it works out of the box.
The reason I'm unsure is that we've been using the Advanced Module Manager(on the JED) extension (free and paid versions available) for nearly as long as we've been using Joomla. Using that I know we can specify whether a module appears on child items.