Did the show take place in a contempary setting, starting with 1988, the year of the series debut? This is a good question and remains a mystery to Colin Chivlers, the director of several first season episodes of Superboy. There was never really any hard-core references to a particular time-frame in the show itself and it is just assumed to be contemporay. I mean, you can notice the cars, the Kevin Kiner synthesizer music and Lana Lang's hair styles (and choice of clothing) that it's the 1980's (and I still like Lana Lang's choice of clothing to this day!). Colin Chivlers stated online in an interview, "Superboy is set in a nowhere time."
If this is accurate, then it was probably done for one good reason: a specific, established time could make the show look 'dated'. If you specifically say in an episode..."it's 1988"...then viewers watching the season 1 DVDs today can say, "Oh, this is old." So it's not exactly about looking at the 1980's hair styles in first two seasons, but looking at what it doesn't say. In terms of when the production was shot, this gives it away indeed. However, by using your imagination, Superboy could take place during any contemporary setting, even today (minus the cell phones, of course).
I think a 'nowhere time' setting is far more accurate in the latter "The Adventure of Superboy" seasons 3 and 4. Indeed, looking "dated" is not good for the future of a new syndicated series, so it was wise of the Salkinds to never pay attention to dates during shooting. But the promotional commercials for the first season eluded otherwise, labeling our hero as "The Superhero of the 90's" when it was still being shot in the late 1980's. So the Salkinds were indeed thinking in advance. Back in 1988, the 90's looked far into the distance. Now, of course, it's in the past.
So, although elusive, this was exciting to hear! Setting Superboy up for the future gave the series the impression of Superboy being somewhat futuristic, or taking place in some kind of 'nowhere time' like Colin Chivlers describes it. If one were to sit back and watch an episode today, it would be easy to determine that seasons 1 and 2 may have been shot in the 1980's,but the time-setting of the show itself is not going to give this away. In fact, you'll have to look at the date on the box to know for sure.
The exception to the 'nowhere time' that Colin Chivlers mentioned is at least one episode of Superboy the TV Series that could be considered a time-piece. It takes place during the roaring twenties. Superboy went back in time in the episode "Hollywood". Not only was the production and costume design dead-on in that episode, but it really had a 1920's feel to it. The music by Kevin Kiner was adjusted likewise.
The production value and scenery with seasons 3 and 4 can definitely be called 'nowhere time' because it was mostly shot at night, with that "Dark Knight" film-noirish shooting-style and seemingly timeless look of the wardrobe and set design. The music became far less of a 1980's pop-synth backdrop to a musical score more cinematic. This 'nowhere time' is most definitely in season 3 and 4 (which stepped away from appeasing to the young audiences and became dark and gothic in nature).
Regardless, an entire Superman TV Series like Superboy is sure to leave a fresh take on the Superman mythos for new generations to come which was far more daring than the later television incarnation "Smallville". Don't get me wrong, "Smallville" is a great show. But the Superboy TV show innocently said yes to flight, and yes to tights and wouldn't have had it otherwise.