Yes, I think the magazine poster I've used for my current version (while being the highest quality source I had) is an early version of the painting, which differs from the final box art in a few more places. Just compare some parts of the ship and the ropes, which got a few additional highlights and details painted in for the final box art:
Of course this might also stem from different scanning or photography settings used back then. But if I should get a chance to work with the "The One" poster, I'll revise this anyway. Unfortunately @m1ckey hasn't replied to my requests yet.