I could be wrong but I don't Moser ever built bikes, but rather contracted companies to build bikes for him. Perhaps earlier '70s models were simply endorsement deals.
Lots of companies use through the stay cable routing, Trek did it a lot of the early '80s bike and I think some of their Aluminum ones too. I have a Bianchi that has it.
I suspect this is something someone rebuilt from a frame. Looks like a nice frame though.
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“One morning you wake up, the girl is gone, the bikes are gone, all that's left behind is a pair of old tires and a tube of tubular glue, all squeezed out"
Sugar "Kane" Kowalczyk