Yup, I do the same when I add zincs to any of my tin skiffs too ! What did I have in my fleet ... 4 there for while? I think so, not counting the 2 I take care of for my boatclub. ZERO issues, by the way, since adding the zincs in the manner shown.
on my '08 there is a bolt on the inside of the bracket too. You can access the bolt throught the deck plate on the bracket. I did place a very small amount of plumbers pipe thread tape on the screw threads of the zinc just to ensure no little leaks. The most important thing though is that the zinc is touching shinny aluminum , not any paint what so ever.
Took the Zinc off today and sure enough it was painted under it. A quick grind, cleaned up zinc, retouched up the paint. Took a total of 20 minutes. Any idea why Parker doesn't do this?