There is a far, far easier way assuming the government really wanted to get the individual who did this.
All federal internet traffic goes through Mount Weather, VA in the East (Denton, TX in the west). Every activity done right down to mouse clicks and keyboard keystrokes are recorded with no expectation of "privacy". It is in fact a part of the agreement you sign every time you take the required network security training every year. So finding out who was accessing Wikipedia at the time of the edits becomes extremely easy.
I know this because I have had access to the federal systems for years. It is a job requirement. I do GIS (among other things) and every time I send a map across the federal network I get a call from someone out of Mt. Weather asking what it is and why I am sending it. So yes, they can identify, by user, who is doing what.