do i get all fields or all information about entity in POST CREATE record

if i am on CONTACT entity and i say after record is created do any other task  so i will use POST CREATE CONTACT message to do my operations. my question is when my plugin will be fired then do i need to service.retreive() to get contact entity record i just created or all the information or all the fields i have already in my context ? i am asking because i have been doing  like this

 Entity order = service.Retrieve("contact", guid, new ColumnSet(true));

TO RETRIEVE  all fields in my plugin for contact i have just created so my question is DO I NEED TO DO LIKE THIS or i have already all information i have just created in my context ?