The way to find out would be to go to the county clerk's site and check on the election results by precinct, then see how the 2 non-reporting precincts voted in past elections.
Unfortunately, the Milwaukee County clerk doesn't have any data for yesterday's election online yet. Most other counties do. I don't think it's a 'spiracy, just incompetence or laziness.
The “precincts reported” numbers on AP aren’t moving even thought the vote totals are. Strange.
The missing precinct in Jefferson (a GOP) County is the Town of Lake Mills. That precinct went for Walker last November by 120 votes, but that was with a turnout of 31,000 in the county outside of Lake Mills. The turnout yesterday w/o Lake Mills was about about 22,200 or about 72% of the November turnout. 72% of 120 votes is a gain of 86 votes or so for Prosser, but that assumes he ran as strongly as Walker did in that county (he actually had a margin 6 points less than Walker did).
In any event, I would forecast a gain of 70-90 votes for Prosser from Jefferson County once Lake Mills is in.