Legal question about reselling something incorporated into something else

Hi, I have an idea for a kind of garment which I think may appeal to a fair-sized specialty demographic. It would have to have a particular design affixed to it; not a trademarked icon, just a certain kind of symbol. Although I could paint or sew this symbol on, it may be easier to simply buy patches with the symbol and attach them. How does this work legally? Would I need to clear it with the patch supplier or what?

I would WAG that the First Sale doctrine comes in to play, but that could depend on what sort of intellectual property rights the original manufacturer might claim, e.g. patent, trademark, or copyright. E.g. I believe that manufacturers can have a copyright on a particular pattern sewn into or printed on fabric, but that a specific “cut” of a garment is utilitarian and not subject to intellectual property rights.

I was on Etsy one time and I saw some hacked garments there - iirc there was someone who would sew skirts onto the bottom of casual shirts and sell them as dresses.

This old thread (started by robert_columbia) discusses “reverse passing off” and the Lanham Act. I don’t understand the issues well enough to say if it applies here.

Thank you, robert_columbia and Alley Dweller. From the looks of the thread Alley Dweller dug up for me, I don’t think I would have to worry. (Though I have yet to look up the First Sale Doctrine.)

It would be the equivalent of, say, putting a peace sign on an apron (thus communicating that hippies, too, like to cook) except a far more unlikely combination. So if I were sewing aprons, and I bought peace sign patches to sew on them, I would be okay? After all, the purpose of a patch is to sew it on things…

Okay, looked up First Sale Doctine on Wikipedia. Even better! Thanks!