my $data_fix = "00";

while (<DATA>)
	{
	my($data1,$data2,$data3,$data4,$data5) = split(/:/);
	chomp($data5);
	$data5 = $data5 . $data_fix;
	$data_line = $data1 . ":" . $data2 . "00" . ":" . $data3 . ":" . $data4 . ":" . $data5 . "00" . "\n";
	print $data_line;
	}

__DATA__
o:200806050852:b7199767:b24211012077030:200902232359
o:201103251457:b6235734:b2421100997663:201204022359
o:201403101021:b8015840:b24211013181843:201404072359
o:201407291225:b8759124:b24211001018862:201408262359

##</code><code>##

OUTPUT:
o:20080605085200:b7199767:b24211012077030:20090223235900
o:20110325145700:b6235734:b2421100997663:20120402235900
o:20140310102100:b8015840:b24211013181843:20140407235900
o:20140729122500:b8759124:b24211001018862:20140826235900

##</code><code>##

my $data_fix = "00";

while (<>)
	{
	my($data1,$data2,$data3,$data4,$data5) = split(/:/);
	chomp($data5);
	$data5 .= $data_fix;
	$data_line = $data1 . ":" . $data2 . "00" . ":" . $data3 . ":" . $data4 . ":" . $data5 . "\n";
	print $data_line;
	}

##</code><code>##

OUTPUT: (note the leading "o:" has been replaced with the "00" which is meant to be on the end of the last field, for some reason??)
0020080605085200:b7199767:b24211012077030:200902232359
0020110325145700:b6235734:b2421100997663:201204022359
0020140310102100:b8015840:b24211013181843:201404072359
0020140729122500:b8759124:b24211001018862:201408262359