The bolt and odd nut at 11 o'clock in the pic looks like one of those spacer deals for the rear dropout that keeps you from sliding the axle too far back. There's actually one on my Voyageur that I keep meaning to remove but haven't.
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A race bike in any era is a highly personal choice that at its "best" balances the requirements of fit, weight, handling, durability and cost tempered by the willingness to toss it and oneself down the pavement at considerable speed. ~Bandera