TC stands for trade certificate,issued to showrooms for transportation of vehicles ONLY N ONLY during business hours,otherwise usage of these numbers is against law,as you stated 143-A this digits have record to which trader it is issued and alphabets from A onwards are kept in record by trader normally this particular series is issued by Sindh excise,in Rawalpindi it is RIP-393-A issued to a Suzuki dealership.The fee for this was 20,000/- per anum in Karachi two years ago.