UPDATE: Oscar Doing Much Better!
Yesterday (Sunday) - a week after "the crash"

- we took Oscar to his regular vet so he could give him a thorough check and review the ER x-rays to make sure nothing was missed.
The vet checked him out very well - massaged and manipulated the leg and shoulder (no yelping! hooray!) and took Oscar walking around the practice to watch him move.
He is still favoring the leg a slight bit at times - especially if he gets too rowdy - but it is much, much better. The Vet agrees that he is on the mend, and has cleared him to start a new obedience class in a couple of weeks.
We are still limiting his walks and play time a bit, but it looks like our boy will be OK in the long run.
When we go back in early November to get his Revolution, I'll have the Vet evaluate again if he is not 100%
Thank you, thank you, thank you for all of your words of support and healing thoughts. I truly belive it makes a difference!