It's always hard to tell things for sure in a picture ... but yes.
His arm does not look right. It is probably borderline, but it's there for sure.
He needs to go to the vet asap and get on a treatment plan to correct this issue.
Glad you ordered the calcium w/ no D3. You will need it for his continued maintenance ... it will not correct the current problem though .... we need bigger guns for that.
-Brad