Can they be? Yes.
Should they be? NO.
The pitch and length were designed to match the respective motor KW ratings, not to be interchangeable. Even though they will fit they are not fully interchangeable, nor are they intended to be. Even though a TH prop will fit a Plus motor adapter, the prop adapters are different enough that it fits loosely. Furthermore, you cannot mount a TH Plus prop on a TH motor because there is not enough clearance in the prop adapter to rotate the prop into the locking latch.
If I could put Plus props on an H480 I would be happy to test the results because I have two, but I'm not going to even attempt this with my Plus. I'll leave that to someone else with an extra Plus.
...Hey @Steve Carr! We are all anxiously awaiting your test results!! Inquiring minds want to know!
It is the Prop Pipe dream of H480 owners, including yours truly! Yes, they are too long, so it's a good thing they won't lock on to the adapters. However, the prop adapters ARE interchangeable, so you could actually get Plus adapters on the 480 motors, but the props would interfere. You would need to use the longer Plus/520 arms to achieve the clearance needed. However the motor footprint is completely different and doesn't easily lend itself to modification. At this point a prop upgrade is more easily achieved by buying a Plus!
...Which I did.