[towndrunk]

It sounds to me like you are on Google Compute not Google App Engine. If you are running on App Engine you would have a *appspot.com domain. Unless you setup a domain with App Engine.

[narayanb]

I don't think so. This is what my billing statement says -

App Engine Backend Instances: 8146.607 Hours (Source: [h-56])

[towndrunk]

There are also two App Engine backends... Standard Environment and Flexible Environment. See here (upper left):

https://cloud.google.com/appengine/docs

Flexible runs on Compute whereas Standard runs on the well known App Engine.