Can I get the FSSpec for a file using the standard FB^3 File$ calls?  If so how?

I need it so I can pass it to a ToolBox call.

I also have another question but it might not be so easy.

I need to find a non-Carbon equivalent to a Carbon call.

EXTERN_API( OSErr )
AEGetDescData                   (const AEDesc *         theAEDesc,
                                 void *                 dataPtr,
                                 Size                   maximumSize);

This call is Carbon only and there is probably a pre-Carbon version but I can't find it.

Essentially, I'm sending an AppleEvent to the Finder and asking it for the global location of the file icon.

in English it's 'object specifier for "bounds of window of container of" object'  In the end I'm getting the global RECT of the file's icon.

The AEGetDescData is just the response from the Finder as best as I can tell.

I'm guessing that this is equivalent but I'm not sure and I'm not sure how to use it:

toolbox FN AEGetParamDesc(long,long,long,@long) = word

Any suggestions or code?