Is there any documentation about the year that the side car loops forging started the welded "dimple" about 3/4" below the upper tube joint? It seems to be quite evident on the 1947 UU frames. I do not see it on the 1946 bullneck frames I have inspected. Is this dimple totally incorrect for all 1941-1945 big twin frames? Is there documentation to back this up? Is it a reason for dis-qualification according to AMCA floor judging? I am really interested in verified original condition frames(in or out of motorcycles) from the 1941-1945 era that either have the welded dimples or do not. Hard core facts are appreciated, speculation is anticipated, and BS is thoroughly unavoidable!!!! Have at it experts!!