Several real modifications to the code base I work on have taken less than 0.05 programmer-hours. About half of which was booting up and connecting to the server.

In this case, it would be a matter of changing something along the lines of this:

<span class="votes " id="score_<? echo $comment["ID"] ; ?>">
<? echo $comment["up"] - $comment["down"] ?> point<? echo $comment["up"] - $comment["down"] != 1 ? 's' : ''; ?>
</span>

and tacking something along the lines of this to the end:

(
<span class="votes " id="score_up_<? echo $comment["ID"] ; ?>">
<? echo $comment["up"] ?>
</span>
|
<span class="votes " id="score_down_<? echo $comment["ID"] ; ?>">
<? echo $comment["down"] ?>
</span>
)

I don't know the exact implementation details server-side on this, as I don't have access to the LW source code, but it really would be a minor tweak (unless upvotes and downvotes are counted together, in which case it would be nontrivial).