We partially disagree with Trap 2, sorry. Every Perazzi receiver is different. The stock will most likely bolt up, but you should have it professional fit to avoid problems down the road. We do this for a living and we have seen so many broken Perazzi stocks. If the fit is not good, it will stress the wood and eventually cause fractures and even full on breaks were the stocks fits around the receiver.
Soft Touch is correct. I know the stock will bolt right up, however, that being said, if you decide to use that stock all the time it should be fitted properly. I have a pretty nice Wenig stock on my MX3 Special that I bought from a shooter in Arizona. It was exactly what I was looking for so I bedded the receiver to the stock with acra-glass to be sure the fit was perfect.... Dan Thome (Trap2)
I wouldn't buy it if you don't have unconditional return priveleges. As indicated, the rib on your gun is higher than on an MX 8 and while you can jack up the comb, if it has an adj comb, you may not like the feel/fit of that. I personally do not. You also may not like the cost of properly fitting it to your receiver. You do not say what vintage MX 8 the stock came off. If it is an early one, it may be a sizeable fitting job at great expense or may not be doable at all.