I'm pretty sure this was the start of an alternative reality game.

Several great character actors in it like Oakland and Greer, and decent production.

But not 1950's production date is 1960. Looks like MCMLX not MCMLI or even MCMLV two points top and bottom crossing. Definitely an X

The copyright at the end says MCMLI .. 1951

Release date: 1960.
Television series pilot for a proposed series that purported to show the circumstances behind a famous unsolved murder. The victim this time out is Martin `Mugsy` Heidel, a West Coast underworld boss who loses all his Hollywood friends when he is accused of murdering a small-time bookie. He vows to create a fabulous hotel, casino and entertainment hot-spot just across the border of Nevada and make it so lavish that the men and women who snubbed him will crave his affection again. When Mugsy plows all the profits back into the hotel, his criminal bosses are not pleased and Heidel is `retired` in a hail of bullets from an unknown assailant in revenge.
Cast: Simon Oakland (Martin `Mugsy` Heidel), Joe De Santis (Mr. Baroni), Lisa Gaye (Catherine Mills), Steve Gravers (Harry), Richard Karlan (Solly Green), Dabbs Greer (Sergeant Croft), Aneta Corsaut (Gloria), Ken Patterson, Joseph Ruskin (Pine Tree Knox), Vici Raaf, Dick Bernie, James Parnell and John Marley (Lucky).
From IMDB.

This isn't really a bad unsold tv pilot, though the lack of a conclusion is probably the main reason for being unsold.

I quite like the cast and production values.

At least it's better than "Gigli"!!