Here's my map (assuming all the Anderson voters would have gone for Reagan):
Probably not a safe assumption; maybe 60% would've gone for Reagan, maybe 20% for Carter, and 20% would have not voted. There would be a small (say, 2%) pro-Reagan swing in the North on top of that, directly from Carter to Reagan, and probably a small, 2% pro-Carter swing in the South. The shifts:
Alabama: Reagan does get increased support from Anderson voters, but then there's a small, 2% swing from him to Carter, which adds up to a narrow Carter victory.
Arkansas: See Alabama.
Hawaii: Increased support from Anderson voters probably gives Reagan a victory. Keep in mind Ford nearly won Hawaii in '76; it was much less Democratic back then.
Maryland: Yup, increased support from Anderson voters gives it to Reagan. There would be a small flip backwards, as parts of Maryland are culturally Southern, but it wouldn't be the full 2%; I calculated a 1% flip, which results in a narrow Reagan victory.
Minnesota: Increased support from Anderson voters. For those of you who note 1984, Mondale was the presidential nominee then; he would've had less of an effect in 1980.
Mississippi: Again, the Anderson increase does not make up for the Carter bump.
North Carolina: This would be the closest state of the election, but by less than 0.1% percentage points, Carter would eke out a victory here.
Rhode Island: The support from Anderson voters isn't enough to give Reagan a victory here, but a small shift of liberals who voted tactically from Carter to Reagan in Northern states (I hypothesized 2% up there) does, by an even narrower margin than in Maryland.
South Carolina, Tennessee: Narrow Reagan victories.
So, yeah, because of the South Carter actually gains: from 49 electoral votes to 76. However, this is still not very much, and they are more regionally concentrated:
