Yes, there is an application named "Videostamper: Add Logo, Timestamp and Text on Video" on the Google Play Store.
The application allows adding different types of a stamp to the Gallery videos. You can add the signature to the videos. You can also add different stamps like
1) Watermark Logo
2) Date and TimeStamp
3) GPS Geotagging Stamp
which will make your video more attractive.
Hope, this helps you.