Isn't the 618FA bezel already shock-isolated? I'd say you shouldn't have any problems with lamps blowing under recoil. On the other hand, I'd say that the KL5 head will fit (looks like a 6P body tube).
yes it is shock isolated. but we know that shock isolation is not always shock isolation. I had a 618FA installed which blew the lamp in the first few shots.....I know, maybe a dud bulb. but will LED's fare better regardless?
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.