I'm with BJ on this. My first thought when I opened this thread was "Have you tried it on Ku yet?"
Chances are if it will work at all on Ku, it will work as is, unless of course it is VERY old as BJ said. Do the "pencil test" and at least give it a shot with a Ku feed.

As for automating, I've picked up several prime focus 5 footers (gray Laser/clone, no name on the center plate or LNB cover) that are conventional C band operator assy equipped. The mesh is identical to my 7.5 Laser that works very well on Ku. Is this what you are reffering to? (I cant believe Anole let you slide without reminding you that a picture is worth a thousand words.....lol)
Keeping the signal from "leaking thru" (duct tape???) is only part of the issue. As I'm sure you know, the signal must be reflected back at the proper angle to the feedpoint to be of any use. C band is very forgiving in that respect compared to Ku but even such actions would yield poor results for C band, much less Ku.
......unless it's a "Mad Scientist" thing in which case by all means proceed and report your findings.

Personally, if it's a prime focus I would attach a legacy (polarotor) C/Ku feed assy to it and see what happens.
That is what is on my "to do list" for my 5 footers.........