The model 7 is a side plate as far as I know. There was the early SO series.
In 1910, Beretta was selling WC Scott and Alfred Field hammer guns. That year, they also had a boxlock model 4337. The 4337 was available with Krupp (vero acciaco - real steel) or damascus (vero damasco - real damascus) barrels. They also offered it with triple or quadruple lock up.
I do not have any catalogs from the 1920's.
In 1932 they had models 1011 & 1050 both of which appear to be sidelocks.
In 1938 they had models 450, S.01, S.02 & S.03. There is a small graphic that seems to indicate that the S series was a true sidelock.
An S.01, the lowest S model from a 1935 catalog. While their best hammer gun sold for 1500 Lira, the S series started at 2200 Lira and went up to 3500 Lira for an S.03
The early Italian guns were the equal of any made at the time. They suffer today from a lack of collector enthusiasm. Beretta steadfastly refused to market to the military for nearly 400 years. WWII saw an end to that policy.
Pete