The answer is yes! For the safety of your puppy and others... the "come" command is one of the most important commands to teach. If the leash or collar broke while walking your puppy on a city sidewalk, it would present a dangerous situation for vehicle drivers as well as pedestrians if the dog bolted into the street. A guide dog handler also must trust his/her guide to be well disciplined and return to him/her
no matter what situation they are in. This is not only for convenience but for safety and protection, as well.
The Southeastern Guide Dogs Puppy Raiser Manual has a chart beginning on page 75 titled 'Teaching Guideline by the Age of the Puppy'. After the puppy has mastered the Sit & Stay command, the handler is able to move to the end of the leash to introduce the "come" command. This is usually introduced to the puppy when they
are 12 - 16 weeks old and practiced regularly until the puppy goes IFT.
Put the puppy in a Sit/Stay and walk to the end of the leash. Call the puppy using his/her name with the command "come". Keep your voice happy and cheerful. Praise the puppy when he/she comes to you. Practice indoors, outdoors, and in other age appropriate real-life situations. After the puppy has learned to come, teach him/her to sit in front of you when they arrive....much nicer than an excited puppy running into you. :)
Once the puppy has mastered the "come" command on the six foot leash, try using a slightly longer leash and practice using the same procedure. The goal would be to see if the puppy could work up to a 20 to 25 foot lead and consistantly come when called. Remember to never drop the leash while working on the "come" command because then you do not have a tool to use to coax the puppy to come.
Just a reminder...never scold a puppy if you have called him/her to come. The puppy will not want to come to you again.
As the puppy gets older and more proficient with the "come" command try practicing the command in a group with other dogs and situations that may offer your dog a distraction. The "come" is one of several important commands a guide dog puppy in training should master.