New cocker owner--is he too protective?

Question
Hi,
we adopted a 3 year old purebred American cocker.  He is neutered and up to date on shots.  We have had him about 1 month.  I have three boys ages 7, 4 and 4 months.  He has been great with them and just about every one else.  He rarely barks.  However, this past week, my son's 8 year old friend came over to pet the dog and he started really barking at him.  The boy ran back across the street and the dog did not follow him.  I told the boy to come back and pet him, because I didn't want him to be scared since our dog is a nice dog.  I was holding him by the collar and when the boy reached out to pet him, he somewhat lunged at him while barking.  The boy was wearing big black snow gloves, a big black coat and a big snow hat.  Would this have anything to do with it?  I put our dog on a leash and walked him up to the boy's home about an hour later.  I told the boy's mom to have him come out without the gloves, hat and coat which he did.  The dog did not bark and allowed him to pet him. Then today the boy came by again not wearing the gloves or hat but he did have the coat.  The dog started barking at him again and almost lunged but I was holding him.  I am nervous and wondering if he is becoming protective of us.  What can I do?  We start a basic obedience course on Monday.  Thank you for your time.

Answer
You did all the right things by experimenting to see what was generating this reaction.  I'd say it was definitely the "outfit" which just spooked the dog.
I'd ask the boy to come to your house again without the "big black gear" and see what happens.  I'd also bet if you snuck the "big black coat" in and just put it on the sofa he'd bark at the coat.

I don't think he's being protective or aggressive..I think this outfit for some bizarre reason just scares him.
I'd write this off as an eccentricity and not worry about it.  Just file the knowledge that people in "big black outfits" might cause a reaction.
Delores