Marx Accessory Parts

I've got three marx accessories that need some replacement parts. First for the 429 street light, I need two bulbs and a screw and 2 nuts for the lights to work. Second is the 423 crossing signal, I need a blub housing and both bulbs, also, all three of the screws are kind of rusty, should I replace them? Finally, I have a 0446 beacon tower which needs a new beacon. The blub on it works and it does fit the other two accessories that need bulbs. I looked on this website but am not sure what I need to buy. For the screws and nuts, you think if I took the accessories to a hardware and see if they have the pieces I need? I have a caliper if I need it.