Status bar codes won't work in commands and are only meaningful to the status bar, at least in general.
You could show a custom confirmation dialog with file counts and other information via scripting, but there's obviously a learning curve if you aren't already at familiar with some form of scripting already.
The Confirm multi-open script looks very similar to what you're aiming for and might be a good starting point, or even a complete solution with no scripting knowledge required, depending on what you want to do.
