Probably not. Here’s why.
Ballots are cast in three different ways. Recounting them is unlikely to change matters.
The first type is cast on DRE machines that directly record the vote electronically. Adding them up again will produce the exact same results.
The second type is bubble-filled paper ballots cast at the polling place or by mail that have been inserted into machines. Those should also produce the same results with only a slightly greater but still very small possibility for change.
Some mail ballots that have overvotes (i.e. the voter filled in voters for more than one candidate). The Board of Elections has already ruled on these ballots, applying the sensible, legal standard based on the intent of the voter. For example, if a voter filled in two bubbles but put an x through Candidate A, it will be counted for Candidate B. Ballots with no clear indication of voter intent will not be counted for any candidate. The Board will apply its decisions in the same manner as during the count.
The final ballot type is votes sent in electronically. In these cases, the votes were transferred from the electronically mailed form to a paper ballot and then fed into counting machines. There is seemingly greater chance for error here except that this process was done very carefully with two separate people overseeing the copying to make sure it was done correctly. I don’t know if the recount allows for examination the copying of these votes on to paper ballots, but it is very likely to change more than a very small number of votes—fewer than needed to change the outcome.
The only potential source of change I can see is if the Board of Elections discovers a missing DRE memory stick or stack of ballots. That is also highly unlikely. One reason that the count took so long was that the Board was being extra careful due to the tightness of the county executive race.
Some of the more extreme Blair supporters (but not Blair) are calling for him to fight to get more provisional ballots included. Except that my understanding is that Montgomery has already counted a far higher proportion of provisional ballots than elsewhere—90% as compared to the 68% state average. That means there are relatively few left and those that are left were excluded for very clear legal reasons, such as the voter was not registered with the party or changed their registration too late to vote in the party’s primary this year.
Alternatively, I suppose Blair could go to court to fight to get other votes excluded. Both approaches are way to reminiscent of “Stop the Steal” for my taste. The Blair campaign has been wise to steer utterly clear of them even as it pursues its legal right and utterly reasonable request for a recount due to the tightness of the election results.
UPDATE: See new post with some corrections.