Yep a prop can cause it to porpise. If they botched the repair job thats the first place i would start. I had a raker for my old champ that i had fixed by a "general repair" prop shop and all they did was grind off the nicks and it was never the same after they were thru with it. I lost a bunch of speed and it didnt have the bite on the water that i had when it was new. The loss of blade surface area was the culprit.
What i would do is see if you can borrow a prop from a friend and see what that does. If that fixes it then you found your issue.
FWIW a polished finish would not cause a boat to porpise, if it did mine would be bouncing all over the place and thats just not the case.
Here is the scoop on polished vs brushed finish from on of the leaders in high perfomance props.
POLISHED VS. BRUSHED FINISH
Here is the truth about a polished vs. brushed finish on your propeller.
Some companies will tell you that a propeller with a brushed finish is faster
than a polished prop - NOT TRUE. Also, I would love to tell you that a polished
prop is faster - but that is also untrue. Yet there are advantages to a
polished prop. Some companies just don't want to take the time and labor to
polish. But it's your prop - and you should make the judgment. If brushed
props were faster, every major company would have a brushed finish, and
you would not see a polished prop anywhere. It's just not true.
Here are the real advantages of a polished prop:
As you know, prop blades crack, especially in high performance "High X"
dimensions. If a crack is starting, you can see it like a crack in a mirror. At
this point, you may be able to repair your prop before it's too late. It is much
harder to see a hairline crack in a brushed finish, and if you loose a blade -
you replace the prop. Also, with a high gloss finish, if there is poor
workmanship - you can see it. A brushed surface can cover up poor
workmanship, not to mention the obvious reason of how good a polished
prop looks at the boat launch!