_msdcs subdomain best practice with NS records?

I have the _msdcs subfolder under my domain (the grey folder). example below

It has only one DC inside of it for a NS server. This DC is old and no longer exists. I checked my test environment and it has the same scenario (an old DC that does that not exist). example below

I'm just wondering:

1) Is this normal, should this folder update itself with other servers?

2) should I be adding one of my other DC's? and removing the original?

I have a single forest, single domain setup 2008 functional level. My normal _msdcs Zone does behave as expected and removes and add the appropriate records. Thanks.