The argument about inserting obsolete weapons into the “Fall Blau” line up is going to fall on deaf ears, since the PzIII B the entry German tank in the Moscow campaign had been withdrawn from service by the time of OP Barbarossa ref: Panzerkampfwagen III Ausf.B (Sd.Kfz.141) - Tank Encyclopedia - cited from Panzer Tracts etc…
The first 8 built Panzer III Ausf. Bs were ready for distribution by August of 1937. Six of these would be given to the Putlos tank training school. The remaining two would be given to the 5th Panzer Regiment. The last two vehicles built, when completed, were allocated to the 1st Panzer Regiment at the end of 1937.
*Despite being built in small numbers, the Panzer III Ausf. B would see some action during the war. Due to the lack of more modern tanks, the Germans were forced to use some Panzer III Ausf. Bs for the invasion of Poland in 1939. The majority (if not all) Ausf. B vehicles that were damaged or required a major overhaul were retired from service and instead given to training units after February 1940."
The PzIII E could be argued to have been used in Barbarossa and as such would be better suited to be an entry level vehicle for the germans, however, it should be swapped out for the F as the more numerous and most likely starting variant (there are some differences between them) ref: Panzerkampfwagen III Ausf.E (Sd.Kfz.141) - Tank Encyclopedia
“For the invasion of the Soviet Union, there were 350 3.7 cm and 1,090 5 cm armed Panzer IIIs. By this time, it is somewhat difficult to pinpoint the precise version of the Panzer III used, as the sources rarely mention them. The identification of the precise version is not always possible, as the Ausf. F looked exactly the same as the Ausf. E. Like in the previous campaigns, the Panzer III was the backbone of the German armored thrust. The German tanks were able to quickly overcome the older Soviets models, like the T-26 and the BT series. The T-34 and KV vehicles proved to be almost invulnerable to the German tank guns. Following the harsh German losses in the Soviet Union, its likely that only a small number of Panzer III Ausf. Es would have survived 1941.”
The more appropriate upgrades to the PzIII J, would be the G or H variants, which are also well documented ref: Panzer III
“The Panzer III Ausf.G was produced between March 1940 and early 1941…The first Ausf.G tanks were armed with 3.7 cm Kw.K L/46.5 tank gun. Some took part in the invasion of Holland, Belgium and France in May 1940. After experiences during the battle of France later versions were armed with the 5 cm Kw.K 38 L/42 gun. They were used on the Eastern Front and in North Africa.”
“The Panzer III Ausf.H was the first version of the tank to be designed with a turret fitted with the 5 cm Kw.K 38 L/42 tank gun and with 60 mm of frontal armour, rather than having these specifications added later in an upgrade program. They started to be delivered in late 1940 and early 1941.”
The PZIII J in game would have come as a very late addition, if at all, into the Moscow Campaign as it was an evolution of the PzIII G and a redesign of the hull. Production only started in 1941, so perhaps some early examples might have made it into the theater by Oct/Nov '41 in time for the events unfolding in game.
Consequently the proposed PzII (F) variant is in game to fill a gameism niche. If you stretch your imagination you could argue that a few units were retained/hidden by Pz Regiments “in the rear with the gear” for use in urban combat situations 
