I work with international dating conventions in regulatory documentation routinely. While day-month-year is a preferred dating method on continental Europe, and to a certain extent preferred in the UK, one will still see both conventions for UK and context for each convention will often be supplied. There is no uniform dating method and it can be confusing at times.
The US generally prefers month-day-year convention, yet even US-supplied documentation differs. Consider the Customs form one fills out for the US when re-entering the US. The dating system is day-month-year. When you fill out your IRS tax forms, however, the requirement is month-day-year.
It is quite possible that Dunham could have influenced the dating convention.
As to the footprint thing, my own father's US hospital birth certificate in 1929 took the print of only the right foot for ID purposes.
Back in 1961 it would have been say, month year...
Footprints...
I wonder if that right foot thingy was a practice in the US in 1961 ???
Also it may have been necessary for ID to get papers to bring the baby back to the US