I'd have add the oem control unit plus wire harness to control my fan, ^^^^^ so i believe goober is right. plus this has been a very interesting project, goober has baked cdi boxes before and had good results, i don't know if it's ever been tried on the oem fan controller, even if it could be, from what i gather this new controller can also be adjusted to cycle the fan on at defrent temps which the oem will not do.
Drivers side, middle or passenger side of the motor? They look too big to be from anything with the shifting star (#6 in fishes reply above) yet too small to be from anything else. Looking at my hand and knowing we most likely have different size of hands it's hard o judge the exact size of the pieces but I have a general idea. I'm not thinking of anything though that would be roughly that size. Knowing if they are aluminum or metal might help as well.
I think this project was started to create a temp monitor with readout as well as a fan controller for TRX300. I’m adapting it to my TRX350A
the sensor for these models are NLA