If you would create images by a thing that is not a so called generative ai system, those images are not gen ai made.
If the thing contains ai code, is not relevant for this question. Neither is it asked, if the compiler used to create the executeable did contain any ai code. Or if the operating system used to develop the game did contain any ai code.
You were also not asked, if you developed the idea of the game by talking to an ai system and getting inspiration. Or if you used a gen ai system to develop play test scenarios.
Some viewpoints about ai remind me of vegans. Like a vegan going to a restaurant and ordering vegan food. But also requireing the waiter and cook to be vegans, the menu not be bound in leather and the candle on the table not be bees wax.
so it would make sense to call it AI graphics
Reverse the question and see if you would still feel so. Would a player seeking games with gen ai graphics aprove of the gen ai graphics tag?
If you promise ducks in a game, there better be some quacking and walking like a duck in the game.