I just came across an old instruction manual somewhere, and here’s how Wheelock specifies polarization of its devices.
Non-polarized: the horn leads are all black and strobe leads are blue
Polarized: for horn leads, red is positive and black is negative; for strobe leads, blue is positive while white is negative. The 7000 series horn/strobes only use black and red wires due to the horn and strobe being wired in series.
And this brings me to something I may have just discovered. The 32 series horns were probably the only Wheelock electromechanical horns to be offered in non-polarized and polarized versions. And that’s why it has “P” in the model number. The 34, 7001, and 7002 horns on the other hand were only offered in polarized versions, hence, there’s no “P” moniker.
However, when it comes to the pigtail and terminal versions, Wheelock kept the “T” moniker, even after pigtail connectors were discontinued at the end of 1985.