It will take a modern one. I will put one on if desired, but you might want to try and find an original spring. This is definitely the coolest knife I have ever had up for sale! The item "Very Rare Victorinox Swiss Army Knife 1946-1950 Vintage" is in sale since Thursday, August 23, 2018.
This item is in the category "Collectibles\Knives, Swords & Blades\Collectible Folding Knives\Modern Folding Knives\Factory Manufactured". The seller is "scoutfinnmemphis" and is located in Greenville, South Carolina. This item can be shipped to North, South, or Latin America, all countries in Europe, Japan.