The breeding will be true if they were the only kind in the area. If they were cross bred with something else you liked or that did well it’s no big deal. Tomatoes aren’t like something like cucumbers that may have been crossed with something else. With cucumbers you want heritage for sure. Last year my heritage cucumbers did really great. I have more land cleared this year and even have my greenhouse up!!! Putting the tilapia tanks in now.
My tomatoes were Heinz variety sauce tomatoes who are supposed to be OP.
From what I’ve read on the gardening threads, tomatoes tend to self-pollinate more than cross pollinate. I have two separate garden plots. I plant all of the same variety in one spot in the garden, and anything else goes in the other spot.