Barry the 21 3/8" measurement of the stand indicates the later, longer field stand. So also does the cut out portion of the bottom ring. The early field stand was shorter and the ring at the bottom was a complete circle. The early field stand had a lug brazed to the saddle spring tube and therefore no need for a clamp on part. Ron
I can't help much there Barry. Although my bike is early and still retains the original stand lug. It's been upgraded to panniers and the longer stand. I suggest you email Henk who has an original on his Deluxe M21. ahum@quicknet.nl Ron