Class 385s mostly use 6 car trains on the Glasgow/Edinburgh to Alloa/Dunblane routes. However, in TSW3 there is no 6 car 385s. Just 3, 4 & 8 cars. As seen here, ScotRail do operate 6 car 385s. TSW3 operates only 3 car units on the Glasgow/Edinburgh to Alloa/Dunblane when IRL it is 4 and 6 car trains on these routes.
You are absolutely correct and for rivet games they should be spending more time at their local railway station Stirling to see 4 & 6 carriages 385s go through them in service.