The one that sounds in the middle register is IMO too high to be a T-128 (even for the newer iterations); but I could be wrong.
I suggest it's an RM-130/Pen 15.
IMO it's more likely that the low-pitched siren is a T-128, tho.
However, if my above guess about the RM-/Penetrator is right, then I'll wager the low toned one is an RM-127, as it sounds right for that particular model.
That's in Conway, AR and from what I understand, they have a system of Thunderbolts and T-128s. I'd imagine that have some other CD sirens there as well as some 2001s but from what I understand, T-128s have been the most recently installed sirens there.