PTA
Approved stock is the quiet part of the launch. It matters more than the color.
Mercantile, GNext, and iSelect described the iPhone 18 Pro and Pro Max units in their September launch as PTA approved. PTCL's Mercantile counters in Islamabad, Lahore, and Karachi are part of that same official path.
A set that is not PTA approved can need DIRBS registration and tax before it works fully on a local SIM. The tax and the paperwork change. Check the current rule on pta.gov.pk before you buy a grey-market import because the sticker looked lower.
Official warranty and Mercantile Care are tied to the authorized channel. A bargain set with no PTA approval and no distributor warranty is a different product, even when the box looks the same.