No, his booster was in July. It's hard to tell on the attached thing. I don't think it feels attached to anything but it's really hard to tell as it's on the back of his front leg.
I don't think it's related but it's probably woth mentioning that we had ooodles of tests done on him a couple of years ago as he has a bald patch at the back of each back foot like a callous. The vets found nothing at all wrong and said it was probably an age thing.
He's 13 now which isn't ancient and my gut feeling is that this new lump's some kind of spot or Smokey-inflicted bump.