I have an LRP SPX Comp Stock Spec ESC and the receiver wire is detached. Not sure which contacts are for the red, black and white wires. Any help is greatly appreciated.

Use a multi meter to find the ground of those 3 pins under the regulator with the white sticker (9100096A) using the continuity test.

You can find ground from the top metal portion of the regulator or the two gold pins above it to the left. Solder in the wire for the receiver negative, positive and signal

You can also meassure with the closest capacitor like the black "220" next to it. The white stripe is the + and the other side is the -
Probably 2 pins will meassure with it, the 3rd pin will be the signal.

This is a video of a guy repairing a LRP flow, not sure how close but it may be good enough to get you some ideas.

+ https://www.youtube.com/watch?v=kIAOn-H2FII" title="View this video at YouTube in a new window or tab" target="_blank">YouTube Video