How do the archaeologists know that Tutankhamun had a mortuary temple? The Egyptians seem to have forgotten their boy-king by the end of the XVIII dynasty, after all. That’s one reason why his tomb was lost until the twentieth century A.D. That, and the fact that when the tomb of another pharaoh, Ramses VI, was built nearby, the rubble dug out of that tomb was dumped on top of Tut’s.
Tut had enough time and power to build that big colonnade at Karnak that Ramses the (supposedly) Great appropriated by having his cartouches replace those of Tut. But at that time, it was roofed, and no one could see that additional cartouches were still up there by the ceiling, so Ramses' chicanery was discovered about 30 years ago.
And, he has a condo made of stone-ah.