[/Users/paul]:: port provides /Applications/MacPorts/Gimp.app/Contents/Info.plist 

/Applications/MacPorts/Gimp.app/Contents/Info.plist is provided by: gimp-app

Yes, but the gimp-app port saves you from having to create an Applescript wrapper by making a wrapper of its own and installing it where you would expect it.  

Someone has already done all this for, if you installed the meta-port.