Maine author and Red Sox supporter Stephen King has agreed to sign a rare, anonymously donated copy of “The Regulators’’ — a book he wrote under the pseudonym Richard Bachman — so that it can be auctioned off to benefit The Emmaus Center, a homeless shelter in Ellsworth, Maine. Money raised from the auction will be used to help locals afford heat. Scottie’s Bookhouse in Hancock, Maine, has the novel on display and is coordinating bids. Store owner Michael Riggs told us on Thursday that the auction has already gone national. “Someone called me on the phone from St. Louis and I’ve had bids from Texas. The current bidder now is from California.’’ As of Thursday afternoon, the highest bid was $1,500. If you can beat it, contact Riggs at (207) 667-6834 or at firstname.lastname@example.org. Riggs says the auction will run through the month.