Its a lot more complex than that.
My report explains how the resins I am aware of being used now are formulated.
Im not aware that any resins used for repair have lead in, or not sufficient to register, but you would have to ask a repairer to be sure

I have samples of the resin used to fill the chips by Mr Whalen for our research as he gave them to me.
He also showed me the 'raw products' he used to make those resins.

I did find some things showed up under UV light, but it was not conclusive. That said, it was ggod enough for me to get a UV lamp for Mr Trimble also, in case he needed it. I bet he hasnt even opened the box

The lead I was previously referring to was solid weights in the center of the chips.
I guess you are referring to 'flecks' in the clay, another way to add weight.
I dont believe that method was in use when the chips I studied were made. Brass yes, but not lead. If there was any lead in the pigment of dark chips maybe then it didnt alter our results at all.