You can only find this free battlestar after unlocking the Signing Back In Loading Screen.
This is the Signing Back In Loading Screen for reference:
You can see the characters running from an explosion at the Motel
If you look closesly you can see a translucent battlestar near some bushes on the corner of a small stone fence. It's hard to see you may have to zoom in on the screenshot.
The Battlstar can be found on the north part of the Motel, on top of a brick wall on one of the sides of the swimming pool.
See screenshots and maps below to help find the location of the secret battle star.