Googlebot expects URL parameter names to be escaped when adding them via Google Webmaster Tools.
I ran an experiment on my site where I created a page with two different URL parameters: unesc%
and escap%
. I created page for the experiment on my site. On it uses the parameters with four values each
I then added escap%25
and unesc%
to Google Webmaster Tools as "Effect: None, Crawl: Representative URL" and sat back to watch what would happen.
The first thing I noticed was that Googlebot actually came to my site and crawled all the parameters, despite the webmaster tools setting. This is either because:
- There is a bug in Googlebot where it doesn't respect the settings
- They designed Gogolebot not to respect the settings
- It takes some time for Googlebot to become aware of the settings. (I put the settings in before Googlebot had a chance to crawl, but it started crawling within an hour).
After Googlebot crawled, webmaster tools didn't report that Googlebot was monitoring any matching URLs. I figured that it would take some time before GWT started showing what Googlebot was actually doing so I waited. A couple weeks later I now get this:

I would still suggest adding both to your site just as a precaution (I'm only linking to the escaped version of the URL, I'm not user if it would be different if I linked to the un-escaped version).
Here is the testing that I had done earlier:
I tested it by adding both, just to see how the tool would react.

I thought that it might give me an error for one of the two, or possibly canonicalize them to the same thing. I could actually add both of them (as you can see from the screenshot).
That leads me to guess that the un-escaped one is the one that would match while Googlebot is crawling. But, that is just a guess. Since it allows you to add both, you might as well just go ahead and add both to be safe.