Another alternative is based on the fact that your data is nicely vertically aligned, even if not perfect. So you could specify which columns of characters belong to which field. This is something that Excel would also offer when importing such data.

use strict;
use warnings;
my %format = (#field  from   to  
          reqid  => [  0,  7],
          dest   => [  8, 19],
          from   => [ 20, 41],
          date   => [ 42, 48],
          time   => [ 49, 55],
          npages => [ 56, 59],
          rcv    => [ 60, 70],
);

<DATA>;
while(<DATA>){
  chomp;
  my %line;
  for my $item (keys %format) {
    $line{$item} = substr $_, $format{$item}->[0], $format{$item}->[1]
+-$format{$item}->[0]+1;
    $line{$item} =~ s/^\s*//; # remove leading spaces
    $line{$item} =~ s/\s*$//; # remove trailing spaces
    print "$item=$line{$item}, ";
  }
  print "\n";
}
__DATA__
REQID     DEST             FROM                     DATE   TIME    nPa
+ges  RCV
138454  mail_room     Marco's Pizza         12/26 21:52    1  rcv     
138446  custsvc      973 618 0577          12/26 18:44    1  rcv     
138445  county2       spam                  12/26 18:41    3  rcv     
138444  custsvc      spam                  12/26 18:30    1  rcv
138439  county2       7182737253            12/26 17:54    2  rcv     
138438  county2       Acme Products, Inc.   12/26 17:52    1  rcv
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