I doubt it. Although the Lockheed Tristar may have been an excellent plane in terms of technique, it didn't do so well from a financial point of view.
Today, airlines are seeking fleets composed out of planes from one, maybe two manufacturers, to save on maintenance costs. Also with aircraft from the same manufacturer, e.g., Airbus, mixed fleet flying is sweet deal. Don't forget that the entire aviation market is changing and the future is still under some haze.
I think that if Lockheed were to re-enter the commercial aviation market, they would have to bring out a whole range of aircraft, not just one. Unless, of course, they produce an airplane that everybody wants and is unique. Right now with a hawkish U.S. government the military industry is well off, and I'm sure Lockheed benefits from them. Aren't they producing the Cruise Missiles? Maybe they need to be restocked?
Just my $0.02.