Probably...
In most cases, I just “try it and see.” If you want to see if the current-user can create a file somewhere ... try to do it. Using a “junk” filename, try to create it (using some system-command like e.g. touch, in a qx// block), and then immediately remove it (same way). Wrap the whole thing in an eval block. If an error is thrown (“$@” is non-blank), you know it didn’t work. Yeah, it’s a hack, but it works reliably when a lot of other things don’t.
There are so many things that can affect file-access, that it is often much more difficult to “guess,” than to simply “push on the gate and see if an alarm goes off.”