During the showdown in the radio studio, the poster on the wall behind Michael Knight changes.
K.I.T.T. lists the most recent date and time of radio airplay of the song used to tell robbers when to strike as 12:35 a.m., but when the deejay is shown introducing the song, the clock in the studio reads 11:18 p.m.
The DJ broadcasting from the club says "Breakdown" is #18 with a bullet. This story is presumably happening in 1983 or 1984, but "Breakdown" was released in 1976. Moreover, it peaked at #40 on the Hot 100, not even close to #18 with or without a bullet.
The robber uses a key to unlock Michael before Michael figuratively turns the table and leaves the thief, unattended, locked to front of his own truck. The thief probably still had that key to those handcuffs, and if not, might have had a duplicate - the thief might have unlocked himself and driven away as soon as Michael and K.I.T.T. left.