If so, does it work at all?

use strict;
use warnings;

{
    package TTT;
    use Moose;

    has fif => ( is => 'rw', reader => '_fif' );

    sub fif {
        my $self = shift;
        33;
    }
}

my $m = TTT->new();
$m->fif(42);
print $m->fif, "\n";

1;
__END__
42
[download]

Update: but s/reader/accessor/ and it would work.