Appdesigner doesn't run applications.
It is a tool to develop GUIs, and writes some of the code for you.
The main difference is that Appdesigner uses a different file's extension, which is .mlapp format, rather than the usual .m.
Note that .mlapp files are still run by Matlab.
If you right-click on the file and go on property (or if you have the file extenbsion automatically shown), you can distinguish between scripts and Appdesigner applications jsut by looking at the format.
Moreover, If I recall correctly, one difference between .mlapp and .m reguards how the callback of the ui components are defined, and also how src and event parameters are passed inside it.
Except for this, I have never had troubles in copy-pasting the .mlapp code to a script, to use it as an .m file.
If you have access only to the code, you can use this feature to know wether the code was based in Appdesigner or not.