I wish I saw something... he looks pretty normal (if slow for a puppy) . Maybe he's had some soft tissue injury. I don't see anything in his radiographs that looks abnormal, except maybe the inner toes look a tad close (I'm not good @ feet but we do have a foot expert here-I dk this will tag? DblTrblGolden2 get a look at these rads!))
Sorry, I just saw this. The x-ray's look normal to me. I've stared at way to many golden retriever foot x-rays the last three years. I also don't notice anything in the walking video other then maybe a slower gait for a puppy. The other thing is the video is taken on a slippery floor surface. I'd want to see him walking on carpet, and maybe watch his gait closely.
My best recommendation for anyone with a golden that thinks they have an orthopedic issue is to go to a veterinary sports medicine orthopedic surgeon. They see so many more growth issues, and injuries. It will save you time, money, and heartache to go to a top level performance specialist. I'm not sure where your located, but if on the east coast I would try VOSM, in Annapolis Junction Maryland or Dr. Roberts at Blue Peal in Malvern PA.
The other thing to know about feet is that goldens only weight bear on certain toes at certain times. You can see an issue at a walk that would never interfere with a run. At the right facility they can put them on a large gait pad, at VOSM it's an entire runway, and monitor how they are weight bearing during each type of walk, jog, run. It's well worth the piece of mind.
EDIT
I just re-read the OP. If he shows no signs of pain, I'd watch it for a while and see what I thought. Keep careful documentation. Take videos of whenever you see the limp. Puppies grow so fast and the way joints look in X-Rays and CT Scans can be interpreted differently by different vets. I was given a CT Scan diagnosis of bi-lateral elbow dysplasia at a top veterinary school when one of my boys was 7 months old, along with genetic sesamoid disease. I thankfully went to VOSM and they said wait and watch on elbows until he was two. They agreed with the sesamoid diagnosis, but not the treatment plan for it. The sesamoids are plates in the tops of the toes that lay between nerves and ligaments. I don't see anything in your xrays that suggests anything like I had. At the age of 2 I took our boy back for OFA's completely expecting to get some mild diagnosis of ED on at least one elbow. He passed OFA's. I even sent them to a few of the specialists that had seen him and they all agreed that it was a developmental issue in the early CT Scans at 7 months. Thank goodness I didn't jump into surgery. Get multiple opinions, and watch carefully yourself. I also kept my guy on rugs as much as possible. I have a home with hardwood throughout, so it was odd for us for a while covering everything in rugs. It helped him get traction and bear weight properly though.
