I don't think it's possible without glue because you put quite some stress on the parts when you close them. I made the model a few times and even glued it sometimes came loose (might be because I used crappy glue). Don't let the fact that you have to use glue withhold you to make it, it's a great model!!
you could add an edge graft to the model to make the tab so much larger that it would go around all the pocket, it would make it much harder to put together because it would be have to take two folds inside the pocket, anyway doing this will add to the model cohesion and maybe you won´t need glue
hope it´s not a bad idea
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