Will I also receive the source code for iOS and Android
No. You will receive the built up app file only.
You will receive the app for iOS (uploaded to app store connect as a build) and Android (mailed to you).
However the source code used to build the app is proprietary. It will not be provided due to the risk of unlawful replication and distribution.
The approach is similar to your bubble app. You own and control your bubble app but not the bubble engine.
Similarly you own your Native App but not the BDK Native Engine.
Updated on: 12/02/2019
Thank you!