“My uncle named his dogs Rolex and Timex. They are his watch dogs”

A joke has it that a person named two dogs “Timex” and “Rolex” because they were “watch dogs.” The “watchdog” pun has been cited in print since at least 1992.
 
             
Google Books 
The Reader’s Digest
Volume 140
1992
Pg. 122:
A FRIEND OF MINE was waiting for her dog’s turn at the veterinarian’s office when a man came in with two German shepherds. The receptionist asked their names. “Timex and Bulova,” he replied. “They’re watch dogs.” — Contributed by Join Hibner
 
Google Groups: comp.sys.acorn.programmer
Shared text sections
Tom Hughes
4/4/95
(...)
.. Wanted a pair of watch dogs, named the pups Timex and Rolex.
 
Google Groups: rec.pets.birds
Budgie Buddies    
Mamabird
1/5/99
(...)
Great names! When I worked for a vet a few years back I got a kick out of some of the names people came up with for their animals. I’ve never forgotten one client who had several dogs. They were named Timex, Seiko, Bulova, etc. and he said they were his “watch” dogs.  😊
 
Google Groups: rec.pets.dogs.misc
need name suggestions
karaoke kate
5/24/01
timex and bullova….seiko and rolex (are they “watch” dogs??)
 
Google Groups: 3do.bad-attitude
rolex and timex
andre
7/29/03
A girl was visiting her blonde friend who had acquired two new dogs, and asked her what their names were.
 
The blonde responded by saying that one was named Rolex and one was named Timex.
 
Her friend said, “Whoever heard of someone naming dogs like that?”
 
Whereupon the blonde responded, “What else are you gonna name watch dogs?”
   
Google Groups: alt.humor.puns
“Puns of the Weak” 08-01-03
Stan Kegel
8/1/03
(...)
Why did the man name the dogs guarding his ranch Rolex and Timex.
Because they are watch dogs?” (Stan Kegel)
 
11 September 2003, Statesman Journal (Salem, OR), “Birds, dogs, etc.,” pg. D1:
A girl was visiting her fair-haired friend who had acquired two new dogs, and she asked her what their names were.
 
The blonde responded by saying that one was named Rolex and one was named Timex.
 
Her friend said, “Whoever heard of someone naming dogs like that?”
 
Her friend said, “Hellooo. They’re watch dogs.”
   
15 February 2004,

(Fort Walton Beach, FL), “Surf Wax can keep dude dog from wipeouts,” pg. C7:
A girl was visiting her blonde friend who had acquired two new dogs and asked her what their names were.
 
The blonde responded by saying that one was named Rolex and the other was named Timex. Her friend said, “Whoever heard of someone naming their dogs like that?”
 
“HellOOOooo,” answered the blonde.
 
“They’re watch dogs!”
   
Google Groups: alt.humor.puns
Kids Puns of the Weak 03-30-04
Stan Kegel
3/31/04
KIDS PUNS OF THE WEAK for the week ending 03-30-04
JEST FOR KIDS – THE RIDDLES
 
Why did you name your dogs Timex and Rolex?
Because they are watch dogs (Isaac, 10)
 
Google Books
The Biggest Joke Book Ever
By Jack Jacoby    
Victoria, BC: Trafford Publishing
2008
Pg. 127:
A girl was visiting her blonde friend who had acquired two new dogs, and asked her their names. The blonde responded by saying that one was named Rolex and the other was Timex.
 
Her friend said, “Whoever heard of someone naming dogs like that?”
 
“HelOOOooo,” answered the blonde. “They’re watch dogs.”
 
Twitter
John Sibley
@jbsibley
Did you hear about the guy who named his dogs Rolex and Timex? They’re watch dogs.
3:16 PM - 16 Jan 2010
 
Reddit—Dad Jokes
My two dogs are named Timex and Rolex (self.dadjokes)
submitted April 7, 2015 by photo238
They’re my watch dogs.
 
YouTube
Jokes - Why did the man name his dogs Rolex and Timex? Because they were watch dogs.
jokesus
Published on Oct 5, 2015
Joke :
Why did the man name his dogs Rolex and Timex?
Because they were watch dogs.
 
Twitter
marjory
@mcastillo79771
A man had four dogs named Rolex, Omega, Timex, Seiko. When asked about the names of his dogs, he simply said, “They are my watch dogs”
10:44 PM - 12 Nov 2017
   
Google Books
Does the Name Pavlov Ring a Bell?:
879 Hilarious Puns to Test Your Wit

By Gary Blake
New York, NY: Skyhorse Publishing
2018
Pg. ?:
The blonde had named her dogs Rolex and Timex because they were watch dogs.
 
Reddit—Dad Jokes
My uncle named his dogs Rolex and Timex… (self.dadjokes)
submitted February 27, 2018 by Godzilla_KOM
They are his watch dogs.