Re: Terry 6's dad's old Lada
Yes, 2101 was a licensed production of 124. With minor tweaks. First batches produced in 1970 had FIAT insignias stamped all over, even on boltheads. 1972 model I happened to have still contained lots of components manufactured abroad - Italy, Japan, Yugoslavia, Hungary, East Germany come to mind.
Bodywork had its own story: for first 4 years, huge rolls of sheet steel were shipped to Sweden for post-processing, then shipped back. Without this extra processing it wasn't possible to punch body panels out of the sheet. Corners were way too sharp for that.
Jimbopedia has differences between 124 and 2101 mostly covered:
"Compared to the Fiat 124, 800 modifications were made in all, including to rear brakes (discs to drums), suspension (for higher ground clearance), carburettor, and some other parts in order to satisfy a wide range of Russian climate conditions, as well as thicker-gauge steel (so the 2101 weighed 945 kg (2,083 lb), the Fiat 90 kg (200 lb) less)"
"Early models included a crank, in case the battery went flat (an item later dropped) and an auxiliary fuel pump."
But this part about the engine is fishy:
"first variant was equipped with a 1,198 cc (73.1 cu in) engine (a overhead valve design, never used in a Fiat)"
All Lada engines have single overhead cam (SOHC) layout, not OHV. Whereas Fiat 124 used OHV and DOHC engines throughout their production run. SOHC engines appeared much later on 131.