From the earliest information, it was stated that the pieces up through 988 were mold 1 and those after that number were revised.

A Mold 1 piece just sold on ebay Click Here to view with the edition #991 that from the sellers photos is clearly a mold 1 piece.

John
You are right about the 988 being the accepted number. I found that information in the 1995 Winter Legacy and the 1996 January Guiding light. I also checked my spread sheets and I do have a 992 "Mold 1" listed.