The highest current 30 horns are the 35T-6 and the 31T-6, both of which are AC horns.
Also according to the link, Wheelock even made the 31T-WS (4-wire 7004T) as well as the 35T-WS. Another interesting thing is that the 31T and 7004T aren’t polarized, but the 35T is polarized AC. Perhaps those models were discontinued shortly after the grille redesign, along with 32PT, 7003T, and all the models with pigtail wires (including the 34 and 7002). I say this because they weren’t listed on the data sheet that I got with my 7002T (it was manufactured in 1990).
And one other thing worth mentioning. If it were the case that Wheelock began switching from pigtail leads to screw terminals around the same time the horn’s grille was redesigned, I don’t think there would’ve been any need to have the “T” moniker in the model number. If you think about it, products that were made after the 7000 series had screw terminals, but didn’t have a “T” moniker to indicate that. The only reason Wheelock had the “T” moniker was because they offered both pigtail and terminal versions simultaneously, and figured making the distinction would make it easier on potential buyers.
There were also times where I was a little confused about “T” standing for tamper resistant grille when I also came across Wheelock bells that had “T” in the model number (e.g. 46T).