Yes. If there is a recognizable person in any of your content, you will need to have a signed model release from that person on file. Lightstock does not require you to upload model releases with your content, but you are required to have one on file if it should ever be needed. It is ultimately your responsibility to have the model release on file.
Here is a link to our recommended model release form - Model Release
We also recommend downloading the app “Easy Release - Model Release App” on your mobile device. It s awesome and will make life much easier for you!