Oh yes, also running is actor Eugene Boggs who appears not to be a threat to win.
All four nominees are members of the SAG board, seasoned performers and knowledgeable union members.
Gilbert endeared herself to the world as Laura Ingalls Wilder, the adorable tyke on the NBC hit drama, "Little House On The Prairie," from 1974-83. She has since blossomed into a lovely mature actress in TV dramas.
Harper is a career character actress who became famous as acerbic Rhoda Morgenstern in "The Mary Tyler Moore" sitcom and moved on to her own show, "Rhoda," on CBS.
Angeltompkins -- who used to be known as Angel Tompkins before she had her name legally changed to the one word version -- is an absolute knockout who has played a variety of roles in TV and movies.
Boggs, who played a small part in the 1996 movie, "The Sunchasers," appears not to be a serious contender for SAG president. Angeltompkins isn't as well-known as Gilbert and Harper.
Harper would appear to be the frontrunner, with the endorsement William Daniels, popular outgoing guild president.
There have been only two previous women presidents of the actors union: Kathleen Nolan (1975-79) and Patty Duke (1985-88), each of whom held the post for one term.
Among past SAG presidents were some of Hollywood's brightest stars, beginning with future President of the United States Ronald Reagan (1947-52).
The first TV star elected president was George Chandler (1960-63), who played Uncle Petrie on Lassie from 1957-64.
In recent years big box-office stars haven't held the office. But familiar faces did: Leon Ames, John Gavin, Dennis Weaver, Edward Asner, William Schallert, Barry Gordon.
As a rule, actors are strong, articulate union members, most of them political liberals.
It is virtually impossible for an actor to get work in movies unless he or she is a member of the guild, although novices are given one freebee.
The guild strictly enforces its rules on hours, working conditions, overtime, fees, child performers and other issues under its purview.
The union was formed secretly in the early 1930s when actors were considered cattle, working long hours for little pay with few privileges.
They could be hired and fired whimsically by studio bosses, producers and directors.
Abuses were accepted by many actors who were grateful just to be working.
Most bosses knew the hams were happy enough to be paid anything for a chance to dress up, apply makeup and show off in front of the cameras.
"We worked in the valley for a shoot. It was hot but we had to wear coats, and there were no bathroom facilities. I can sure remember that stress."
"In one scene Charlie slapped my face. It wasn't a stage slap. He hit me so hard I fell down. It took him eight times to get it right. My face was swollen.
"Chaplain told my mother, 'If it's not real, it's not good.'
"Actors are a strange breed because they'll do anything," said Berle. "They'll work for nothing just to perform."
Top stars haul down $20 million a picture, thanks in some respect to the guild.
It took courage to join the guild during the Depression when studios hired detectives to seek out trouble-making actors attempting to unionize.
Using the old Hollywood Masquers Club, early SAG adherents held organizing meetings meetings.
Among those early recruiters were character actors Alan Mowbray, Boris Karloff, Ralph Morgan, James Gleason, Richard Tucker, Clay Clement and Claude King.
Their persistence paid off when SAG was formed and won recognition from the American Federation of Labor, seeking fair wages and working conditions for all players.
SAG became affiliated with the AFL in 1935, but it wasn't until 1937 that studios accepted its jurisdiction and suddenly every actor had to join.
"We were finally treated like human beings when the guild got its contract," said Lew Ayres.
This week 100,000 SAG members will vote for a new president, but the turnout will be a minuscule 20-25 percent of the membership.
Said SAG spokesman Greg Krizman, "The percentage is lousy. Many members don't work much and some just belong to get the retirement and medical benefits.
"But SAG is strong and financially sound, and it's a very, very good organization for actors."