I can’t say for certain, but think it’s highly likely that the TPS is the same on both models.
However, TPS faults are usually either a broken track on the potentiometer inside or a dead spot where the wiper doesn’t get a connection to the track. The fact that you’re able to get a sensible reading by turning it further suggests that the fault may be that the idle adjustment on the carbs has been wound up miles to try to compensate for another issue. That would also tally with the excessive idle speed.
<edit> Just looked at a pic of some 400 carbs and now think they're not likely to share the same TPS.
(Though I still think yours may be OK.)