According to a letter from Bill Harris in Robin Snyder's The Comics Vol 23, No 8, August 2012, he wrote all the Phantom stories at Western/Gold Key. However, years earlier Harris had written in The Comic Reader #32 that new stories (not adapted from the comic strip) were being written by Dick Wood. This is a new story.
At http://martinohearn.blogspot.com/2021/09/a-trapani-ghost-on-ghost-who-walk…, script-spotter Martin O'Hearn attributes the script to Dick Wood.
Letters from Susan Strawn, James Williamson, and James Scott Stone, with replies from the editor.