If you can't find your weapons in Gomorrah that's because they're not accessible for some reason. In all the other casinos you could steal your weapons back but here it's different for some reason.
<br />There are safes containing the weapons but they're not reachable without glitching or console commands. There's also a safe containing your companion's weapons. Because of a glitch it's possible for your companions to not even get their weapons back after leaving Gomorrah.
<br />With this fix the safes are placed in an accessible area.