Here is a test file.

package MyTest;

use Data::Dumper;

sub import
{
     warn Dumper \@_;
}

package main;

BEGIN {
    # code to keep use and require for complaining 
    # that there is no MyTest.pm file
    $INC{'MyTest.pm'} = 'testfile';
}

sub handle_error{ die; }

use MyTest +autodispatch =>
         proxy => 'use';

BEGIN {
require MyTest;

MyTest->import( +autodispatch =>
                proxy => 'require',
              );
}
MyTest->import( '+autodispatch' =>
                proxy => 'require as string',
              );
[download]

The output

$VAR1 = [
          'MyTest',
          'autodispatch',
          'proxy',
          'use'
        ];
$VAR1 = [
          'MyTest',
          'autodispatch',
          'proxy',
          'require'
        ];
$VAR1 = [
          'MyTest',
          '+autodispatch',
          'proxy',
          'require as string'
        ];
[download]

The only really interesting thing I see is that

    +autodispatch =>

and

   '+autodispatch' =>

are not the same.