[mrein3]

To answer the original question:
What years are tower clamps correct for?
I would say any car I haven't serviced or don't drive.
I was taught by a VERY reputable mechanic that you never re-install a tower clamp.

So I would say based on the evidence provided by other posters, your truck probably did have tower clamps from the factory but during normal servicing you got the better worm drive clamps.