The actual story in this episode is not impossible,but it definitely strains credibility as it is pretty unlikely. But let's put that aside for now.
The first year of Rockford Files was all over the map. There was a definite learning-curve,as many different tropes and generic characters seemingly fought for inclusion in the early episodes of the first year.
It seems like the series-creators tried just about everything,sifting through what did and did not work as they went along.
Among less-capable hands this might be a recipe for disaster,but this writing-team learned quickly. Long before the end of season 1 the show had the basic outlines of what would prove to be a winning formula for many years to come. In the second season the writing tightened-up,there was more proofreading apparently,because the cases were more believable,the characters and show seemed to hit their stride.