“A guy walks into a bar…” is a typical form of what has been called the “bar joke.” A popular seal joke is:
   
“A baby seal walks into a bar. The bartender says, ‘What’ll you have?’ The baby seal says, ‘Anything but a Canadian Club.’”
 
The joke has been cited in print since at least 1995. “Club sandwiches, not seals” is a saying based on the same message.
   
 
Wikipedia: Seal hunting
Seal hunting, or sealing, is the personal or commercial hunting of seals. Seal hunting is currently practiced in nine countries: Canada, The United States, Namibia, Greenland, Iceland, Norway, Russia, Finland, and Sweden. Most of the world’s seal hunting takes place in Canada and Greenland. Canada’s largest market for seals is Norway.
             
Google Groups: alt.tasteless.jokes
a baby harp seal walks into a bar
johnny rocket
3/26/95
a baby harp seal walks into a bar.
the bartender say, “what’ll you have, baby harp seal?
the baby harp seal says, “anything but canadian club on the rocks!” 
 
Google Groups: rec.humor
Bar Jokes
Lynn M Wiegard
4/27/95
(...).
A baby harp seal walks into a bar.
The bartender says, “What will you have, baby harp seal?”
and the baby harp seal says, “Anything but Canadian Club on the rocks.”
 
Google Groups: alt.tasteless.jokes
Baby Harp Seal walks into a bar, etc. etc..
Bill
12/2/97
A Baby Harp Seal walks into a bar.
Bartender:  “What will it be?”
Harp Seal:  “Anything but Canadian Club on the rocks!”
 
Google Books
Notes on a Beermat:
Drinking and Why It’s Necessary
By Nicholas Pashley
Polar Bear Press
2001
Pg. 194:
A seal walks into a bar. The bartender says, “What’U you have?” The seal says, “Anything but Canadian Club.”
   
Google Books
A Prairie Home Companion
Pretty Good Joke Book
By Brian Becker
Minneapolis : HighBridge
2003
Pg. 130:
This baby seal walks into a bar and the bartender says “What’ll ya have?” The seal says, “Anything but a Canadian Club…”
 
Google Books
Guy Walks Into A Bar…:
501 Bar Jokes, Stories, Anecdotes, Quips, Quotes, Riddles and Wisecracks
By Michael Lewis
New York, NY: Black Dog & Leventhal Publishers, Inc.
2005
Pg. 84:
A baby seal walks into a bar. What can I get you? asks the bartender. Anything but Canadian Club, the seal says.
 
Google News Archive
17 May 2008, The Day (New London, CT), “New Funnies,” pg. D1, col. 1:
A baby seal walks into a bar. The bartender says, “What’ll you have?” The baby seal says, “Anything but a Canadian Club.” —John Yannacci, via e-mail.
 
Twitter
Kevin Carson Ⓐ
‏@KevinCarson1
Seal walks into a bar. Bartender says “What’ll you have?” Seal says “Well I sure as hell don’t want a Canadian club.”
9:36 PM - 11 Feb 2016