It's possible they kept them, we really don't know. It's hard to say what kind of long term digital storage they were looking at back then. By 2005 it was standard practice to save all these digital masters of films, but in 1997-1999 there was no such thing as digital masters because it hadn't been done. Especially when you consider the state of HDD storage back then. I wouldn't be surprise if there was no actual "digital master", probably what happened is that the individual shots were printed onto individual negative segments and then edited together by a neg cutter just like a regular film. So, in the somewhat unlikely event that the digital files weren't wiped out after the film came out, they are probably in piecemeal individual states and not conformed to an edit, because the negative was cut together and then colour timed in the physical realm, not the digital realm.