Yep, though they sure phrased it oddly. The guy should have just said that detonators are required. Also, a "pipe bomb" is a device, not an explosive. He should have used gun powder or BP as an example of a "low explosive".
It's no wonder we have so much trouble with the ATF and their idiotic definitions when they are so lacking in precision. It wouldn't have surprised me if the guy had added, "...and rockets are explosives 'cause they gots stuff that burns in 'em."