Well, I got another look at Gringo's 'hock' sore today. Actually, a chunk of the scab peeled off. Still not bothering him at all. For that, I'm happy.
That left front, though, is a totally different story. He's still lame on it and just walking in from the pasture, he's very lethargic. I gave the vets a heads up... but I think I'm just gonna monitor for the time being.