Similar to the G1 original toys, there is now the MP series still being manufactured and sold. Japan Taraka also launched the imitation G1 version of Hercules
To you said the temperature-sensitive color-changing logo, Taobao are sold everywhere, that logo has long been not en that as a genuine logo.
Toys in general are sold on Taobao. If you want to make sure it's genuine, you can go to Toys R Us in a big city, where genuine Transformers are sold, but the price is a lot more than Taobao. Or get a friend to buy them on behalf of you from Japan or the United States