Since these models are exclusively used for items, rather than blocks (even if item forms of blocks), shouldn't they be in the models/item folder instead (potentially dropping the "inventory" marker as well)?
Examples:
[MATERIAL TYPE]_fence_inventory.json and associated template model fence_inventory.json
[MATERIAL TYPE]_wall_inventory.json and associated template model wall_inventory.json
[MATERIAL TYPE]_button_inventory.json and associated template model button_inventory.json
Can confirm.