Absolutely!! Expose the pup and acclimate him to all kinds of people, animals, sounds, sights, etc. Do not force the dog if he shows fear, but simply calm him (the book "Calming Signals" is a big help in this area) and reward him when he displays curiosity and not fear.
The only caveat is that you should keep the dog away from unvaccinated dogs and other dogs' "leavings" until your pup is fully vaccinated. But exposing him to other dogs you know who are healthy and vaccinated is not a problem.