This scenario includes Panzer III Ausf. D and E units. I'm not sure what stats designer Bill Jaffe (R.I.P.) had in mind, but in my consolidated units spreadsheet I lumped these two Ausführung into a single unit, the Panzer III Ausf. D-E. This is because they were armed with the same main gun (1 × 3.7 cm KwK 36 L/45) and had the same armor thickness (30 mm all around except rear). The main difference between the two seems to be that in the E the suspension was switched from leaf-springs to torsion-bars and it used six larger roadwheels per side.
So, in summary, there doesn't seem to be a compelling in-game reason to differentiate between the two variants.
Interesting aside, Bill also included this Panzer III variant in his 2015 scenario "Counterattack at Radekhov." He gave the unit one point more in Firepower Against Vehicles (5) than I ended up giving it in my spreadsheet (4); my justification for this decision is in the spreadsheet.