You'd probably need a custom plugin to do it, or if the custom weapons plugin is based purely on the skin id and name, you could set the name to match under ItemPerks.
Like:
"Admin LR300": {
"Item shortname": "rifle.ak",
"Item skin": 2400056213,
"Restrict enhancement": true,
"Announce in chat when this item drops for the player?": true,
"Send a UINotify message to the player when this item drops?": false,
"List of perks and modifiers that the item has [perk: modifier]": {
"ScientistBane": 0.25,
"Durable": 0.25