That P60 was a dud.
The KL5 will stand up better to recoil compared to an incandescent.
It is a straight swap with the 618FA's Z32 Shock Isolated Bezel.
The KL5 is slightly larger diameter to the Z32. If you don't have the latest version of the 618 (with the light grey grip) then there may not be enough room.
Another thing is that the KL6 does not mate like the Z32 does with the Classic L60 Lamp Module Body. However, it fits and functions.
I have no idea how well this combination holds up in use. I doubt there will be any issues.