I'm "reasonably sure" that I should be able to get enough - the gal who originally picked them spends a lot of time in the mountains, and it appears that she got quite a few of them. They are currently in her freezer, packaged very carefully.
If all else, fails, I have "an ace in the hole" - I was in the mountains this past weekend and we found quite a few bushes with ripe berries...and even more with un-ripe berries that should be ready in a week or two.
And, I also noticed, it looks like the chokecherries are going to be very plentiful this year, as well!