Check for the updated Original Tax receipt it is a computer printout. Manually written in the book. Call up Karachi CPLC - 021 35681111, 3568 2222, 3568 3333 request for car update by giving them registration number, engine number & chassis number.
yes you can pay the tax in Karachi at designated National Bank branches handling government accounts like pensions & taxations - one is at M.A Jinnah Road next to Nishat Cinema.
If the tax print out is not there and manual entry is appearing that is not enough. 2ndly - MVT & Excise departments are Returning Original Files of every vehicle you may also ask someone your friend to verify if The file is in record has been returned to the owner's - will cost your friend Rs. 500 and 1 hour at Excise office. --
If the car has Sindh Number and the book is from Punjab MVT& Excise there is no issue get it verified from Lahore MVT& Excise dept for tax & genunity of papers.