There are a couple of minor issues with putting a 444 steering wheel on a 544. I have one hanging around in the garage that I used to have on my old 122 *way* back when. Definitely a much nicer 'vintage' looking wheel, as compared to the bakelite 544 and 122 wheels.

The good news is that they will bolt onto the steering shaft, same splines. And the horn button makes the same sort of contact.

As you've already surmised, one small issue is the cancelling pin. You need to yank it out, and drill a new hole in the proper position (I forget where, really) and put in a new pin.

Then there is the issue of dish. Probably for safety, the later model wheels place the hub farther forward, with the arms reaching back to support the rim. I think the 444 steering column was a couple of inches longer. When you stick the 'flat' 444 wheel on the shorter 544 (or similarly shorter 122) steering colum, it tends to move the rim forward by a couple of inches. This may or may not be a good thing ergonomically (depending on how long your arms are). But it puts the rim too close to the turn signal lever and gear shift. You can bend the turn signal lever slightly at the base to compensate. The gear shift will come close enough to the steering wheel to pinch your hand as you go into reverse and you will probably want to shorten it by an inch or two (although now I recall you have an automatic in your car).

Then there's the slight issue of the 444 steering wheel being very thin, thinner than even the meager 544 wheel is. Can be painful on the fingers. I've solved this in the past by using that double sided hockey stick tape and wrapping it around and around to build up some nice thickness, then topping it off with a leather steering wheel cover.

For some reason I've never gotten around to putting that 444 wheel on the 544 yet. I have shortened the shift lever by a couple of inches, so I'm at least a step or so closer. The 444 wheel sure does look better.
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'63 PV544 rat rod, '93 Classic #1141 245 +t