Back in 1980s the only foreign public bus purchased by USSR was Hungarian Ikarus, while definitely different buses were used for filming Moscow. Also the truck selling gasoline suppose to be military judging by its khaki color, which MUST be Soviet made, but is obviously foreign.
In Ivanov's Moscow apartment he greets his family "utro" ("morning" in English). But it doesn't work in Russian. The only correct way is to say it in full "dobroe utro" (good morning). Obviously but mistakenly copied from common way to cut it short in English - "morning".
Road signs in Moscow scenes are messy. For instance, Vladimir passes sign "no vehicles allowed" and some meters after you can see the sign "parking forbidden" which means a vehicle suppose to disrespect 1st sign to succeed in disrespecting then the 2nd.