Interesting thoughts TD - I think I am seeing a little more clearly where you are coming from.
As you say Rev 7 is explicit in having two classes. The 144,00 and then the Great Crowd. The GC by definition survive Armageddon. I would agree that all the time the WT held to the view of the appointing of the 144k being completed by 1935 then you could only be prospective "GC" post that.
Of course, the fact that the time has marched on so long means many born subsequent to 1935 are dying off and could never have been part of the GC in terms of surviving through Armageddon.
Witnesses would, of course, class these people simply as part of the "other sheep", a class not supported directly by Rev 7, but fairly easily claimed as a group based on the statements about Jesus having sheep "not of this flock". Regardless, past WT doctrine would still limit the OS to post 1935.
I would suggest that the recent change to the view on the 144k being sorted by 1935 does open up the opportunity to say that a Christian over the past 19 centuries could be either 144k or OS, but I don't think they have ever directly said this or even implied it.
I am not sure that this matters to a Witness one way or the other. Revelation 20 is clear about a resurrection so they would simply say that the anyone who died pre Armageddon as a faithful Witness gets a resurrection and this causes no contradiction with Rev 7 only referring to the 144k and the GC who live through Armageddon.