Here is an outcome of the experiment i did, a chrome extension to replace default phone mockeup of appinventor with Samsung Galaxy Note 5. Anyone can use this to change mockup for them too.
Please note that this is just an experiment, and you may get some bugs and erros feel free to comment beow if you found any, And the extension is open source, so you can also have a look at code and modify it according to your need. You can even change phone mockup to anyother phone. Also it's not yet published on Chrome store you'll have to manully downlaod and use it.
Click here to download this Chrome Extension from GitHub
Do hit button If you like my work. Enjoy!!