I concurr with Bastians assessment...I also examined this frame closely for a friend who was interested in buying it...We ended up walking away...Irrespective of whether it was 'right' or not (and I thought it wasn't) it would never fit in with peoples expectations of 'normal practice' so would always have its provenance questioned...From the dimensions I'd say the extra bracket was probably added for the head steady of an OHV engine that came from a swinging arm frame...Ian