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this model three-tube 531 plain gauge
expect you would discover a pillar size of either 26.2mm or 26.4mm
dropouts appear to be either Campag Sport 1010/1 or the the Agrati replica thereof
since you have satisfied yourself that they are unmarked that would indicate the Agrati version
both have the small hole to accommodate the spring of the Campag Sport model gear mech
due to lugs am thinking frame earlier than stated date
do not wish to question that it may have been purchased new in 1974 but it appears to come from a slightly earlier time
a bit odd that dropouts exhibit eyelets while fork ends do not
fork ends appear to be true forged as a raised area around track nut can be seen...or this may be just a washer...
this usually makes one suspect a fork replacement
crown appears to be Vagner model DL
Ernest could be quite eclectic when it came to selecting bits for his frame construction at any given moment in time so it is best not to place too much weight on catalogue representations...
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