Don't say your location, but I've had Doug Jones (shop near M-59 & Crooks rd) make pins, springs, etc..as needed.
He has (as I would think most gunsmiths do)a collection of assorted spare parts ( from ? ) that he can root through & usually find what will
fix whatever needs repair. If it's a solid pin, or a solid pin will do the job, buy a short piece of rod (or tubing) & cut it to the length you need.
Can try hardware store, Home Depot, Lowe's, etc to find material you need.