1) A weapon shop is made through a script whether or not you're using a Mod. Some Mods will provide more functionality for your shop than others, but you CAN make a very basic weapon shop using the official FPSC V1.09 and up.
2) Change the properties of an entity from "Dynamic? Yes" to "Dynamic? No" to make it immovable and without a script. This saves on processing time since the entity will simply be there for looks and nothing else. To make it HAVE a script, but still be immovable change the "Immobile" property of the entity to "Yes".
The one and only,
Those who live in the past, are destined to insanity. Those who live only for the future, will be slaves to their ambitions.
Those who live in the moment... only they, are truly happy.