Welcome Doreen!
Yes, you are certainly right about sesame not being labeled as well as other allergens. I'm assuming that you are in the U.S. - because here in the U.S. sesame is not considered a top 8 allergen (btw, my son is sesame allergic as well).
If you want a quick reference to high risk foods with tree nuts and sesame, visit FARE's website. They have a resource section with pocket guides you can print out.
I'm rushing off to work now, so I'm hoping some other members will chime in with info for you. Summers tend to be a bit slower than normal here, so please be patient if you don't get a quick response.