I bought mine already, a few months back. It is a NIB Old Stock (unfired) 17-6 4" from 1989 without the underlug (not many made). Still haven't shot it...won't buy ridiculous ammo. Here is a photo:
It is a good companion for my 17-4 8 3/8".

It is a good companion for my 17-4 8 3/8".