#!/perl/bin/perl

use strict;
use warnings;

my @files = <c:/perl64/myfiles/*>;

foreach my $file ( @files ) {

    open my $file_h, '<', $file or die "Can't open $file: $!";

    while ( <$file_h> ) {

        print "$file $_" if /\b1203\b/;
        print "$file $_" if /\b1204\b/;
        print "$file $_" if /\b1207\b/;
    }
}