Originally Posted by
KerryIrons
Yes, it is one of hundreds of "hand made" steel forks from the 1950s through the 1970s that were made in the tens of thousands. There were many different brands of lugs in those days, and builders often hand filed them to get a specific look. There is nothing about that fork that could provide significant guidance to the builder.
It appears to have been intended for a recessed brake mount, something that only caught on in the 1980s.