There was also a model 1303 listed in the years 1948 and '49. The main difference between the 1300 and the 1303 was the addition of 'built-in vibrato.'  According to catalog illustrations, it was actually labeled vibrato, rather than tremolo, which is a more accurate description of the effect. This 'organ-like' effect didn't come without a price; the 1303 was $20 more than the 1300, coming in at $85.50

Click for a full view