The E series International Match value is due to its value to collectors. I doubt you will see many in use in competition on a National level. I still use one in club matches, and for the most part they are very accurate. They were built to higher standard than the factory production 52’s. The IM’s were built in the custom shop at Winchester and had to pass a stringent accuracy requirement with both Winchester Super Match and Eley Tenex ammunition. They are not all that rare, with over 450 built. They were offered with 3 trigger options, the factory Winchester Micro Motion, Kenyon and ISU Kenyon. The regular Kenyon trigger was the most popular of the 3 choices. 

Steve