The above discussion is very interesting, what follows is more or less the condensed (and hopefully clearer) conclusion:

You can only distinguish between the first three and the last three calls:

package Classname;
sub method {
        print ref($_[0]) ? 'Object method' : 'Class method';
        print "\n";
}

package main;
my $obj = bless {},Classname;
my $arg = 1;

# calls here

method $obj $arg;
Classname::method( $obj, $arg);  # added Classname::
$obj->method( $arg);
"Classname"->method( $arg);
method Classname $arg;
Classname::method( "Classname", $arg); # added Classname::

__END__
prints:

Object method
Object method
Object method
Class method
Class method
Class method
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Also note (as pointed out above) that the Classname::method calls (so, calls 2 and 6) do not support inheritance, as they are not actual method calls, but 'normal' subroutine calls pretending to be method calls.

-- 
Joost       downtime n. The period during which a system
            is error-free and immune from user input.
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