As long as the templates are consistent, its pretty simple. You probably have each printer template in a separate file, so read each file into a hash of hash of hashes. Something like:

use File::Basename;

opendir(DIR, "/template/dir") or die "can't open dir: $!";
# I'm guessing at the template extension if there is one
@templates = grep { /\.tmpl$/ } readdir DIR;
closedir DIR;

my %printers;

for my $file (@templates) {
 open (FH, $file) or die "Error opening $file: $!";
 my $name;
 while (<FH>) {
  chomp;
  my ($tmp_name, $value) = split /\s*:\s*/;
  $name = $tmp_name if $tmp_name;
  $value =~ s/,$//;
  $printers{basename($file)}{$name}{$value} = undef;
 }
 close FH;
}

# Now %printers contains all valid printer attributes
# and their values
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Update: I didn't write code to compare versions, but lets say you do the above once for the old version, once for the new version, so you have two hashes:

my (%old, %new);
...
for my $printer (sort keys %old) {
 print("Printer $printer not in new\n"),
  next unless exists $new{$printer};
 for my $name (sort keys %{$old{$printer}}) {
  print("Attribute $name not in new for printer $printer\n"),
   next unless exists $new{$printer}{$name};
  for my $val (sort keys %{$old{$printer}{$name}}) {
   print("Val $val not in new for printer $printer attrib $name\n"),
    next unless exists $new{$printer}{$name}{$val};
  }
 }
}

# Then do the reverse comparision looping over %new
# I'm sure you can figure that out
[download]