FALSE COLORS. Paramount, 1943. William Boyd, Andy Clyde, Jimmy Rogers, Douglass Dumbrille, Tom Seidel, Claudia Drake, Glenn Strange, Pierce Lyden, Roy Barcroft, and Robert Mitchum. Screenplay by Bennett Cohen. Directed by George Archainbaud.

   Figure this for the plot of an imaginary film noir: Let’s say there are three War Buddies (maybe Alan Ladd, William Bendix, and Hugh Beaumont) who pick up a fourth towards the end of the war. The new guy, a veritable orphan, forms an attachment to his surrogate family of war buddies, and when he learns inherited a lot of money from the father he hasn’t seen in years, he impulsively writes a will making his new pals beneficiaries in the event of his death — which, as you might expect, comes around very soon and rather suspiciously thereafter.

   The buddies, of course, have no intention of accepting the money, and when they get out of the Service they journey to their late pal’s home town — and discover an imposter there in his place, along with a cute-kid-sister-in-distress! Something sinister’s going on, and with Douglass Dumbrille and Roy Barcroft around, it’s easy to see what.

   Okay. Now substitute a Cattle Drive for the war, make the three buddies cowboys and the inheritance a ranch, and you have the real False Colors, an intriguing Hopalong Cassidy effort with a fine cast of heavies, including Bob Mitchum, still in his “Right, Boss,” days. There’s the usual riding, running and shooting amid splendid backgrounds, a nice knock-down-drag-out between Boyd’s and Mitchum’s stuntmen, plus an interesting performance from someone named Tom Seidel (who?) as the neurotic buddy and his feckless impostor.

   Seidel’s performance, in fact, is one of those bits of desultory inspiration that make “B” movies so much fun to watch: It’s basically a nothing part in a pot-boiler movie, from an actor whose career never went anywhere, but he’s in it for all he’s worth, quietly, intelligently working up his act, and investing it with thoughtfulness and energy, even when he must have known no one would be watching.

   As for the rest, well, this was among the last half dozen Hoppy films produced by Harry Sherman, and it shows. Sherman’s care is still there in the excellent photography, locations and stunt work, but comic relief Andy Clyde is a bit tired, and Jimmy Rogers is no match for James Ellison or Russell Hayden, who preceded him. Young Bob Mitchum graduated in importance to the point where he could match stuntmen with the star, and his fellow-heavies are their usual nasty selves, but a tinge of weariness had settled in, and…

   â€¦and actually it serves the story rather well, familiarity breeding a weary worldliness (or maybe a world-weariness) that would emerge a few years later in the cynical heroes of film noir — and foremost among them, Robert Mitchum.