That '81 article is pretty damaging to it's current position. If I ever get asked if I believe that the FDS is God's channel for communication on earth today, I will say something to the effect of: "How can I believe that when they where confused as to who the FDS even was until 98 years after Christ was enthroned! They didn't even realize when they were appointed, and what they were appointed over. How can I believe that they are God's channel if they couldn't get that on simple thing straight 100 years ago?"
In my head, I've played out the possible scenario of being asked the 'apostasy question' about believing the GB is the FDS. I think I'll start with "First, I'd like to point out that you didn't believe that until a couple years ago." Then say something like "there's actually some pretty firm scriptural evidence that this is not the case" and pull out the '81 WT article. Depending on the situation (i.e. if I really don't care if I'm DF'd) I might add - "this article makes it clear that anyone that insists that the GB is the FDS is an apostate!"