To me the telling part of this whole story is
now tribes are sharing the seeds with each other and with small farmers to bring the plant back.
. I am not sold on this story being "truthful" because;
Firstly, the different tribes of that area would have engaged in trade and they would have started this trade long before any Europeans showed up on Turtle Island.
Seeds were always one of the top trading items, since they represent many different things to us, they are a precious item and held great value.
Secondly, the squash would have been planted every year that the pony soldiers didn't stop them from growing food.
Seeds would have been carefully saved and stored for the next years planting as well as for trading to other tribes.
Now the clans are sharing seeds, this is a good thing.