This rifle appears to be a late prototype of the Model 77 which was manufactured from 1955-1962. It bears most of the standard markings and features of the model as released to the public while having the experimental serial number "E1" marked on top of the receiver and empty front and rear sight dovetails. It is likely that this was one of the last prototypes before public release. With a metal factory tag marked "W 856". The included FN America Certificate of Provenance identifies the rifle by model and serial number, stating that it was previously a part of the Winchester Factory Collection where it was maintained by U.S. Repeating Arms.