My extended, ported XX-Full Mossberg X-Factor choke was stamped "lead shot only".
Truthfully, you could probably shoot HTL through it and be just fine. It's just that one round that might damage your choke, barrel and possibly even the shooter.
It's not worth it... especially when there are numerous chokes on the market that will deliver better patterns. In fact, my XX-Full choke was consistently the WORST patterning choke in my inventory.