On the Arramberi versions the tangs are generally broader than with coil sprung Perazzis so the stocks don't fit. The Arremberi design was later taken over by AYA and known as the MD2/4/6/8 depending on cosmetic level. Used ones still fetch good prices and they still make occasional batches of them.
For interest, Victor Arramberi was a designer at Perazzi until a falling out, after which he went to Spain and started up making Perazzi clones. When the Spanish gun industry was amalgamated, AYA took over the Arramberi design and Victor himself went to Kemen to design the KM4.