A comparison of three Oldenburg JR 91 wappen two Officer and one OR:One more OR's from a helmet in my collection. This one is very similar in size to the one above...screw posts as well.
The officer wappen with reservist cross comes from Amy's JR 91 officer helmet. You will note that the coat of arms shield is flat and more like that of the OR's unlike the silver frosted, bulbous example from my wappen collection.
Thanks for the extra photo examples Steve and John. My officer wappen came off a made up Oldenburg Officer helmet I bought back in the 80’s as a novice collector. The wappen was good but the JR 91 kokarde was a repro. You could also see marks of the original Prussian plate in the shellac. I kept the Oldenburg plate, put on a Prussian Officer and kokarde, sold the helmet. I think I did ok in the end.