They should be ok if they were dry, the only way to know is to sow them!

Hi,
Well, you may have not killed them, but you definitely shortened the life of them. Many veggies seeds stored properly will last a few years if not longer as you may know.
Since it is just veggies seeds which don't require difficult germination techniques, you can do the paper towel germination test if you are worried that they may actually be dead.
Just moisten(damp not soaking wet) a paper towel wrap the seeds in it. Put that in a baggie and place in a warm spot like on top of the fridge. Start checking for life after a couple days. Most veggie seeds will sprout in a few days this way.
Remy

I did this with a pack of dwarf white MG,I accidentally left it inside my lighting unit! :O....so,I planted them all in a panic...lol...guess who will have lots of those this year!...lol..

I agree with Remy. The prolonged exposure to heat would shorten the storage life significantly. If that was combined with high humidity (were there growing plants in the greenhouse?) & the seeds were in paper envelopes, some seed death is entirely possible.

As Remy pointed out, germination testing of veggies is not difficult... and if the seeds were damaged, it could save you from disappointment, by giving you time to procure fresh seed. Even if the seeds pass germination testing, I would not recommend saving them beyond this year.