I’ll dig it up tomorrow and take new pics to aid in this discussion. Kudos for resurrecting the exploration. Personally I think what I have was used as the static version in the mannequin’s hand. Well, half of it.
To recap, a mannequin stands in front of the Batmobile when it screeches to a stop, so the version of the prop does not need to incorporate the spring open capability or be quite as polished as a hero version would be.
As far as props from this movie, many are still missing. For example I don’t think we’ve ever actually seen a real ‘89 batarang in the wild.