Until the middle of the 19th century, shoes had no designated right or left fitting.
Before then, like the ballet shoes of today, both shoes of a pair were the same shape and size–the soles cut to a uniform last for each size. And you broke the shoes in to fit your feet–just as dancers do today–with the leather or fabric softening until it was moulded (or not as the case may be) to each foot.
And that was the case whether it was a pair of formal pumps or riding boots or satin dancing slippers.
If you were male, you might have the width of your calves measured so that the boot top fit about your legs, but the concept of accomodating the instep and the arch of the foot and cutting a sole with an obvious right and left just didn’t exist. It literally had not crossed their minds that it would be desirable to do such a thing.
So the next time you’re looking at a full-length portrait from the period, or in a costume museum, take a look at their shoes…