I think the question was not how to extract the fields, but how to exclude duplicate records.

I think in this case it's easiest to just use a hash to record the names, for example:

my %seen=();

...
while(<INPUT_FILE>) {
  my @fields=split /=/;
  $fields[1]=/^(\d+)/;
  my $id=$1;
  $fields[2]=/^(\w*)/;
  my $name=$1;
  $seen{$name}=[$id,$fields[5]];
}
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If a name occurs several times, the last occurence is recorded and the other ones discarded.