So, are there those that believe that these original Parker stocks were stained with alkanet?

Some were, but not all:

Just to clarify my earlier post, which may not have been easily understood:

I have no idea of what Parker used in terms of stain. Each of the old gun companies seemed to have their own. Sometimes they mixed it or had it mixed/made to their wishes.

It might have included alkanet root. Or not.

Winchester's stain included black walnut husks.

In England, alkanet stain was common. That's all I meant to point out.

Again, Parker's stain could have been anything...

BD, that's beautiful wood !