They could put it where it doesn't look ugly. Like what Ruger does by putting their lock in the grip.

There are 2009 production 642 and 442 revolvers without the internal lock. I just bought one

On the "Pro Series" revolvers, such as the 686 Stock Service Revolver, it has a forged hammer and trigger.

Base on these two production runs, you might be able to buy a new S&W revolver with forged parts and no internal lock in the future.