Actually I had it the other way around in mind, with the slugs for the railguns and discs being easy to make (though the slugs I was thinking need to be iron,) but the weapons taking more materials (and thus more time) to produce. Most vanilla weapons for the dwarves will be replaced by "native" copies of leftovers from the battle at Spearbreakers or designed by Mr Frog (things like chain weapons needing small mechanisms and chains or railguns needing magnetite rails for example.) The crossbow I think will be the exception as until we have the time and parts for things like the disc launchers and railguns themselves we'll need those to stand in for them.
The only real syndromes that appears to be present outside the radiation zone ones are the new ones meant for domestic creatures and possibly the scythod for spawnification (assuming a dog, donkey, or what have you survives a run in with a spawn, just for added paranoia if animals get stuck in.)
I will say four our needs the railguns the stranded Ballpoint and Parasol personnel bring will be significantly less powerful by a very large margin and breaking them down for spare parts will probably be the better option there. to elaborate
1 native railgun requires the following
1 power cell. These can be produced onsite from a specific workshop, using gold and copper bars, or alternately gold and copper wiring tools and something else metallic for housing. This obviously powers the weapon. For a steep price they could be purchased in bulk (say, a box of five power cells) from home or if we have them as allies, Parasol. Of course this would be an abstract representation of them.
2 rails. These can either be produced directly from magnetite or from iron and taken to the same shop as the power cells are made to be magnetized.
1 metal housing. To limit how many can be produced, possibly limited to iron, steel, or admantine, just to make the weapons more valuable and the loss of one being considered horrible, what with these metal typically being harder to come by.
2 small mechanisms. Produced in batches of three, so two batches would give you enough mechanisms for three railguns. One representing the trigger, one the action for the railgun loading a fresh slug.
1 stock. Can be made by a metalcrafter or carpenter, simply to balance the weapon somewhat and make it easier to aim.
1 unit of leather for padding on the stock for comfort while aiming.
Alternatively, we can also by and salvage railguns from enemies/allies who have them, and disassemble them for half or a quarter parts (say always producing a housing and one mechanism, but the other parts being a sort of random chance to get because they were damaged either by the dwarf taking it apart or in battle.)
The disc launcher would be much simpler. My personal vision being either just needing a crossbow to be reporuposed/modified or a crossbow and "disc launcher arms" tool, which would be possible for either a wood or metalcrafter to make. Ammo for combat would need to be made of any weapons grade metal though. I tried the bone and wood discs and they just made the things they hit mad while copper discs took off limbs.
Of the weapons, all the chain weapons would require a chain, power cell, and two small mechanisms. Chain weapons would be intended to shred through armor like it didn't exist, hence the need for things like the small mechanisms and power cells to make them.
Essentially a bare minimum of much more basic weapons would be on hand for production, since the better stuff would take alot of time/resources to make. For example:
generic swords set up between a long sword and short sword
Hatchets for woodcutting (or for the axedwarf who prefers speed)
mughammer - Spearbreakers' reach through its mugs was great indeed. Replaces warhammers for dwarves.
Polearms (normal spears and pikes)
And for the "unarmed" fighters, simple mugs (bashing people of course) and the fist spike (think railroad spike with a handle for punching people.)
Crossbows - Untill we have good shots and the stuff to produce them, railguns are a later-on type deal unless we get lucky on the embark. Would also have a blunt damage mug ammo, unless a separate mug-shooter is decided to be better for that.
Other cultures would of course have the likes of weaker railgun variants, blackpowder weapons, and other such things for us to use too.
.... I got a little too into that, and a lot of it losses coherency even to me but you get the idea. Honestly I kinda favor long production chains to get a single hard hitting weapon. Getting everything made and finally assembled and it getting inaugurated with a spawn or goblin exploding into gristle on the tree behind it when struck... Ahh....