Oh hell yeah.
Actually a good idea is to not just watch as the weights go up but watch the whole evolution.
First of all the 405 pulls were a very good example of how to "go for broke" by a fairly advanced trainee who is really ready for it and has become intuned to what his body is doing.
ROM was allowed in the thoracic region for instance while the lumbar never went into any dangerous end range of motion.
Now the thing to watch for is how that 405 in the near future is not longer a "go for broke" lift but a normal everyday lift. That in itself is progression. In a way it is even more important than simple weight on the bar.
If he were to be getting ready for a deadlifting competition then hitting 500 would be more important than pulling 405 easy. But you pay for that later. Being able to pull 500 does not equate to "strength" in every sense of the word when you find that dropping the weight entails much the same form!
Notice you will see many powerlifter types who ALWAYS look like they are going for broke even when they are 100 to 75 pounds off their max. They don't "perfect" it. So after a while, they don't own the weight...the weight owns them.
As much as I want to encouarage someone I am also looking at whether I will still be "encouraging" them a year from now or whether I will be "rehabbing" them