Hello Adam,
Based on what you have described, your method seems to be the simplest way to do it. You can not only check whether the executable files were created, but you can also check to see the modification dates to make sure that they are from the latest build.
To check if they exist, you can use the following batch command to check if a file exists:
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
IF EXIST some.txt DOSOMETHING
Good luck!
Kameralina