For those who can read Japanese, TakaraTOMY's official TF site has mistakenly labelled the link to Sparkless Seeker as "PF WFC-04 Starscream" and Starscream as "WFC-20 Sparkless Seeker" The thumbnail images and links are correct, but the names have been switched.
https://tf.takaratomy.co.jp/

Here's a screenshot with English captions added.