It's definitely got a mascle stop, but I'm not so sure about the pinecone(?) before DON. If it is a pinecone, then the reverse isn't listed in Withers. Is there a leaf on the breast? If so, then it could be a leaf issue. Withers notes the Walters example, but says there is a leaf after CIVI, which this one doesn't have space for. The key will be trying to see what is after HENRIC. Try cleaning it up a bit.