Re: 1939 Carcano XVIII Terni 7.35 cal. SA Crown Looking for value
The R.E. stands for Reggio Esercito or Royal Army (At that time, Italy was a kingdom; Mussolini was the Prime Minister). Terni was the Italian arsenal where the gun was made.
The S.A. stands for Suomen Armeija, or Finnish Army. During WWII, Finland was allied (reluctantly) with Germany, since the Soviets were correctly seen as the greater threat to Finland. The Finns wanted German weapons but Germany needed all its own rifles, so they sent the Finns Carcano rifles obtained from Italy.