Not sure what this is, but doubt it is even a Masi. No Mais GC I've seen w/ fast-back seat stays. Maybe someone else can tell. I agreee with his caution in the ad, "beware". If we get a consensus I do believe a "flagging" is in order...
https://nashville.craigslist.org/bik/5703900509.html

For Sale: Cash only!!! No Shipping!!!Vintage Italian Racing/Road Bike. Light weight; only 23 lbs as built, total weight. Must be ridden to appreciate the ride and feel the speed of this bike. Restored with both new and refurbished parts. Some Campanella parts. Vintage Nisi Italian wheels. Local calls to phone number listed. I check area codes, beware. Pick up from my residence. Price negotiable. $650 cash.