I knew there were variations for earlier sets, but wasn’t aware of this for 1985, as it’s not even mentioned on Greg’s site either. I have a lot more gloss back than non gloss, so I have to believe it’s rarer if it’s a variation.
From what I've seen, I'm leaning toward the non-gloss backs being the rarer, as well. Before I had responded to your post, I checked Greg's 1985 page, and nothing had been updated, yet. Then again, the video that he points the variation out in was only loaded up to YouTube within the last few months, and he probably hasn't had the time to revise the info for that set.