I wouldn't worry about it. The casing is just that, a casing, the same as a steel pipe would be. The detonator is dead and that cannot be re-manufactured unless you are a pro. If you are, the BATFE is already at your door anyway. My son has a demilled baseball grenade. No problems although I did not let him put it in his luggage on his last flight to see grandma.

Regards,
Bill