Instead of using the string form of the hash reference just take the numeric to begin with. If you wanted the hex form then just pack/sprintf it.

]$ perl
my $h_ref = {};
print 0+$h_ref,"\n";
print unpack('H*',pack('L',0+$h_ref)),"\n";

135099932
80D761C
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__SIG__
use B;
printf "You are here %08x\n", unpack "L!", unpack "P4", pack
  "L!", B::svref_2object(sub{})->OUTSIDE;
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