https://www.marineshop.net/nco-sword-500438
https://www.usmilitaryswordsonline.com/Marine-Corps-Swords_c_59.html
https://www.amazon.com/Marine-Corps-NCO-Ceremonial-Dress/dp/B07MTC35D1/
I cannot attest to the actual authenticity of any of those sources.
But I would bet pretty heavily on marineshop.net to sell you legit, good-to-go gear.