Construction, playability,intonation,what ever comes to mind. Do they play and sound that much better than Gibson/Fender? Here is my comparison: The '91 has an ALDER body and a maple top. To be fair, I think the '98 was more perfectly fit and assembled, probably also due to the accuracy of the CNC machines.
If a guitar has a number of 89321, for example, it was probably built in 1987, but it could have been assembled a bit earlier or later than 1987. The serial numbers are a bit hard to date because there was no uniform way they were assigned a number at Bernie's original shop.
This system was used for the guitars distributed by L. In the late '70s as production grew, the serial numbers begin to get ahead of themselves since only 1000 numbers were available in a series.
Rich in 1974, a system of serial number coding began using a 5-digit code (XXYYY) with the first 2 digits indicating the year and the last 3 indicating the production number.
In mid-2009, the prefix was changed to “ICF” on some instruments, indicating that they were made in Indonesia at the Cort factory were Fender-branded.
Both the “IC” and “ICF” prefixes are followed by an eight-digit number, with the first two digits designating the year of manufacture, (i.e., , , etc.).