Perhaps the problem is somewhere else in your code. Filling in the blanks a little, it seems to work for me.

package Foo;

use Scalar::Util qw( refaddr );
use Carp;

my %a_of;
my %b_of;

sub new {
    my $self = \do{my $x};

    bless $self, __PACKAGE__;
    $a_of{ refaddr $self } = 'a: ' . rand;
    $b_of{ refaddr $self } = 'b: ' . rand;

    return $self;
}

sub puke {
    my $self = shift;

    print $a_of{ refaddr $self }, "\n";
    print $b_of{ refaddr $self }, "\n";

    return;
}

sub get {
    # pasted from OP
}

package main;

my $o = Foo->new();
$o->puke();
print 'a --> ', $o->get('a'), "\n";
print 'b --> ', $o->get('b'), "\n";
print 'c --> ', $o->get('c'), "\n";
__END__
a: 0.917827691956521
b: 0.0455599141746177
a --> a: 0.917827691956521
b --> b: 0.0455599141746177
Use of uninitialized value in print at /home/kyle/perlmonks.pl line 58
+.
c -->
[download]

If you're trying to write one get method in some other package and import it into each inside-out class, that won't work for the reasons Joost has already mentioned.

Instead, maybe you should use the access methods available on the object. I did something like that in Make an inside-out object look hash-based using overload..

    sub FETCH {
        my ($self, $key) = @_;
        my $getter = "get_$key";
        return $self->$getter();
    }
[download]

This way, you don't expose any private attributes, and you go through the proper access method, which might have some code in it more complicated that returning the attribute raw.