So, over in the Have you ever seen ... ? (Questionable products topic), Mike Kuo asked (in 2003) about whether or not these two products exist:

1023 Templars Tower of Time  
1024 Guildwar

Neither the Tome of Treasures' Underworld Publishing web page nor forum list those among the published products, which include:

Lore of the Crypt (all 1991)
Adventures
New Rules, Races & Classes
Spells
Monsters & NPC's
Magic Treasures

Modules (all 1992)
O1 Harbringer of Doom
P1 Sweet Wall of Death
P2 Gladestorm

Gladestorm lists Templar's Terrible Tower of Time as coming in August 1992:

Templar's Terrible Tower of Time is a mega-module written by Christopher Painter.  An evil priest seeking immortality attempts to change his own past and the characters are the only ones who can stop him.  The adventure spans ten tower levels and ninety-nine years of an uncertain furture.  This is one module that you cannot afford to miss!  Available August 1992.

Anyone know more about this adventure, or the other mentioned by Mike, Guildwar?