I've been watching replies to the post I made over on Case's Collector Forum site. Haven't heard from any CASE staff yet. Their guidelines for posting in their 'Ask Case' thread suggest allowing a few days, maybe up to a week to hear from staff (IF they reply). But other regulars there, including collectors posting images of many of CASE's biggest blades, have all agreed the knife in the posted pic is likely NOT a genuine CASE blade. None have seen anything like it, in terms of the blade profile or the length (especially).
A suggestion was made there from another member, to post over on the AAPK site as well, as there are some knowledgable collectors of CASE's big blades over there too. Maybe not a bad idea, if looking for as much constructive input as possible.