Need some help decoding 833 PLEASE...

Those numbers don't make much sense as you have already found. The numbers are on the passenger side of the case. and 1968 was the first year to have the raised boss for the VIN and serial #. 833's between 62 and 74 (as far as my book goes) have numbers between 2400238 and 3780234 but 2973980 isn't on the list.