Would killing the holdout guard at casinos prevent them disarming me in the future?

Based on the answer to this question there isn't a way to keep my weapon hotkeys after being disarmed apart from using mods. If I can't keep my hotkeys, can I instead stop myself from being disarmed?

If I discretely kill the holdout guard in casinos will he respawn or have another guard take his place? Could killing this guard prevent me from being disarmed when I enter a casino?

For 2 of the 3 weapon-confiscating casinos, yes.

I tested it out using the kill console command on the three door greeters at The Tops, The Ultra-Luxe, and Gamorrah. After being killed, no other greeter took their place.

For both The Tops and The Ultra-Luxe, killing the doorman had no effect; meaning once they're dead you're free to enter the casino and gamble, etc.

With Gamorrah on the other hand, if the doorman dies the Omertas will immediately become hostile towards you, thus barring you from using the casino.

I also tested the difficulty of killing the greeters without using the console, and it's surprisingly a lot easier than I expected. Using a Stealth Boy and a hold out weapon, you can simply sneak up behind them and kill them without anyone else noticing. This can also be done at a relatively low level, thanks to the effectiveness of the stealth boy.