Yes, every station used to have fixed number of seats and you could get your reservation out of those seats only, I remember traveling like that, in the 80s.
By the way I stumbled upon this
http://www.irfca.org/index.html, it's a Indian Railway Fan Club, got nice history of the Indian Railways also read the FAQs on the operation very informative.
You know there are 8 links with pakistan but only one is operational through wagha...