Jerry Moos wrote in part regarding the LeJeune frameset on ebay currently: .. unless one insists on being really anal and using French threaded crankarms and pedals. In fact, I'm not even so sure LeJeune would have used French pedal thread in 1974.
My 1973 full Campagnolo LeJeune came with 9/16 x 20 crank arm threading as imported to the West Coast. So, no need to go on a scavenger hunt.
A frame this size would have had a headtube transfer of the same type as seen on the fork legs, or a shield with blue text on a white background also stacked vertically.
It is still one of my favorite bikes.
John Jorgensen
Torrance Ca USA