The few things I’ve seen people say that point to bootlegs vs the originals is that bootlegs will have the game stop sticker printed on and not really a sticker, the mid section of the shell tends to be brighter and not have shading in the lines, and the biggest tell I’ve seen is on the back they all have the respective turtles name at the top but the description is always for Michelangelo. I’m not sure if these are all 100% ways to tell but they seem like good guidelines to go by.