My son's teeth appeared in an unusual order (molars first!) and his canines were among the last to go in. If you are worried, the dentist can do an x-ray to make sure all of his teeth are there. We did that because my son did not have any teeth at 18 months.
It has been a long road, but all of his teeth are in (last molars are just finishing up now). Your son is most likely fine - some kids just teeth differently. If it makes you feel better to check - I recommend doing it. I know I was relieved to see the x-ray of my son's teeth that were taking their sweet time in appearing.
Good luck.