In the attached worksheet from Compustat NA Funda database, separate GVKEYs appear for two Enron Corps: ENRON CORP and ENRON CORP -OLD, both covering 1973-1994. The total assets (Column G) of the two are identical within a decimal point.

The -OLD designation appears for other companies but, for at least some of them (e.g., Conoco), their data are not duplicative. Have you encountered the -OLD suffix? Any idea what it means? 

Any idea how to identify and drop duplicative observations from the data set?