Torn acl, not limping?

My dog just turned 8years old 3 weeks ago. He's a medium-large 73lb long haired pointer mix.

After a rough romp with some dog pals he starting limping. Got some xrays and vet assumed torn acl. Surgeon did a physical exam and said yes torn acl but not sure how bad. I scheduled the surgery.

But my dog isn't limping for the last week. And I've held off on the anti inflammatory meds.

I guess im just wondering is anyone can give me any insight from expereince or if there are any vets in here. Does it make sense that he doesn't have a limp? I literally have no problem doing the surgery if that's absolutely what he needs but I'm scared ill put him through a surgery with a rough recovery thats not truly necessary?

The surgery isn't scheduled for 6 weeks (earliest I could get). I was considering getting him re-xrayed before the surgery or even taking him somewhere else for another opinion??

Thanks in advance.