These just appears to be retcons. The original dice (if that is even what they were) were presumably no longer available. (The original dice were probably not, after all, intended to important keepsakes of Han's.) Lacking precise information about what they looked like, Disney just invented new ones with new decorations.
The dangling decorations in the Millennium Falcon cockpit in A New Hope are small and metallic, resembling dice.* These have conventionally been interpreted as being actual cubical dice, based on the real-world practice of hanging pairs of dice (most commonly, giant plush dice) from the rear view mirrors of cars. From the first time I noticed these ornaments, I thought of them as small metal dice—although they were much too small to make out whatever might be engraved on them while watching A New Hope, even in a theater.
However, it is possible to get a better view of them in some still images (where they are not swinging around at all). Here are two, one a still from Episode IV and the other a behind-the-scenes photograph of the incomplete cockpit set.
Take a look at those dangling pieces up close.
It is not even really clear whether they are cubes. However, what there is no evidence of is engraved patters on the surfaces. The streaks left by the light at continuous curves, with none of the additional specular reflections that you would expect to see along the edges of an etched pattern.
Why the Disney filmmakers redid the dice more than once is more of a puzzle, but the props may not have been coordinated during the making of the films; some of the work on them was going on simultaneously.
*The ornaments are not longer present in the cockpit by The Empire Strikes Back. That can be seen in this image of the cockpit during shooting (although it is easy to verify just watching the film).
