Sounds good.
There is a Finnish book by Esa Muikku and Jukka Purhonen "The Finnish armoured vehicles- Suomalaiset panssarivaunut 1918-1997".
It says:
page 20: "Thirty Sturmgeschütz 40 Ausführung G assault guns (Ps 531-1 to 30)of a planned total of 45,from contract #1189, arrived at Pori harbour in three shipments: 6 July (10), 13 August (8) and 3 September 1943 (12)."
and:
"They were produced at Alkett (Altmärkische Kettenwerk GmbH) in Berlin (10) and MIAG Mühlenbau und Industrie AG) in Braunschweig (19).
The hull of one assault gun was manufactured by MAN (Maschinenfabrik Augsburg-Nürnberg) to the PxKpfw III Ausf. M specification."
also same page:
"The first vehicles were issued to the Assault Gun battaillon on 2 September 1943. By June 1944, the vehicles were further modified by the Assault Gun Battaillon:
- original spaced side armour plates were removed
- German 7.92 mm MG 34 machine guns were replaced by Russian 7.62 mm DT machine guns
-spare road wheels were moved to racks on sides of fighting compartment
-a wooden equipment box was constructed on the engine deck"
I hope this helps.
Cheers,
M.S.