I wouldnt disagree too much with that with. At least not a tribal system along the same lines as those of Pashtuns or Balochis. But even Wikipedia decides to name Jatts, Gujjars as tribes
List of Punjabi tribes - Wikipedia, the free encyclopedia. Todays Pakistan is not pre 47 Pakistan. The effects of Hinduism have to a large extent(in other places still are) going away.
The only tribe in the urban areas who I have seen fiercely make sure that their offspring marry within the tribe are the Syeds. Again the reverence for Syeds by some Pakistanis is the only aspect of Pakistani society that could be considered a somewhat equivalent of the Hindu caste system.
Moving on I am fine with the word "clan" as well, because again it does not imply any inherent status of a group of people within society. My problem lies with the fact that in the South Asian context, the word "caste" is naturally associated with the hindu caste system which the Pakistani Punjabi system quite simply does not follow.