All have agreed to participate, depending on their schedules for that day, says Dennis Frye, president of Association for the Preservation of Civil War Sites.
Because actors' schedules are so erratic, they are on call for any job, Frye says, adding that they have donated their time for the project.
"We want to be there to show we care," Falci says.
Proceeds will benefit the association, which is dedicated to battlefield preservation. The association, headquartered in Hagerstown, is marking its 10-year anniversary, and the program is part of a four-day conference that begins today.
The program starts at 8 p.m. and will include clips from "Gettysburg" and interviews with those involved in making the film. The movie won't be shown, but audience members will receive a firsthand account of what it was like to be part of it, Frye says.
"It's a terrific opportunity to learn about the movie from a Hollywood perspective," Frye says.
The movie doesn't glorify war; it reveals the willingness to sacrifice for one's beliefs, Frye says. He says "Gettysburg" was the most accurate movie ever produced about the Civil War soldier.
"It explores the whole aspect of human decisions and the responsibility for those decisions," Frye says.
Frye will host the program, and he and Falci will interview the actors about their roles.
The evening could be a one-time chance to see the actors together talking about their roles, says Mike Wicklein, producer of the retrospective.
"It's the only time this has been done, and they may never do this again," he says.
The 1993 movie was based on the late Michael Shaara's Pulitzer Prize-winning book "The Killer Angels."
Morgan Sheppard, who portrayed Gen. Isaac Trimble in the film, was invited but won't be able to participate because he is working on a production in Canada, Wicklein says.
Besides Falci, those who have said they will attend are Gorman; Ron Maxwell, the film's director and screenwriter; and Jeff Shaara, Michael Shaara's son and the author of "Gods and Generals," which recounts the events leading up to "The Killer Angels."
Jeff Shaara is writing the last book in the trilogy, the sequel to "The Killer Angels." He will talk about what his father's book and the movie have meant to his family.
Maxwell worked for almost 15 years to bring "Gettysburg" to the screen, and he will discuss his frustrations in making the film, Frye says.
Maxwell's purpose wasn't to film a documentary about the battle, but to make a movie that would tell people what happened, says Falci, who served as a historical adviser for the film.
He says playing Hill in the movie was an experience he treasures, as he always has admired the general.
"It's not a large part, but it's an important one," Falci says. "I'm proud I got to portray him in the film."
The longtime Civil War buff is president of New York Civil War Round Table, and he portrays Hill when he participates in re-enactments. Falci will speak to Hagerstown Civil War Round Table tonight on the topic "Thunder and Lightning: The Relationship Between Generals Jackson and A.P. Hill."
Falci says Friday night's program at The Maryland Theatre will be like a mini-reunion for the "Gettysburg" cast.
He keeps in touch with Lang and Gorman, and last fall he worked with Elliott and Tom Berenger - Gen. James Longstreet in "Gettysburg" - on the film "Rough Riders" in Texas. "Rough Riders," set during the Spanish-American War, is scheduled to air on TNT this summer, Falci says.
Falci has been asked to portray Hill at the Battle of Antietam re-enactment in Sharpsburg this September.
"I will be there in my red battle shirt," he says.