Hi
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southpaw Welcome to Armorama
I don't have any references on the A6M2N Rufe, but I do have a picture of the interior of an A6M5 showing the seatbelt arrangement. It appears to be just a lap belt (no shoulder strap) and the buckle seams to be on the left. I will try and scan the pic and post it here.
This is a picture of the etched fret from the CMK cockpit detail set for my Aichi Val. The belts at the bottom, numbered 5 and 6 are the same type as in the picture of the A6M5 cockpit.
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Hope This Helps (HTH)
Mal