Complex sentence: In the last few airframes of the series a new panel with the same "vertical tape" guages that were used in the original Sierras were introduced, these were known as an A24-not to be confused with the first Sierras which were A24R models.
Split into simpler sentences: In the last few airframes of the series a new instrument panel with the same "vertical tape" gauges that were used in the early Sierras was introduced. These models were known as the A24 and are not to be confused with the first Sierras, which were designated A24R models.