Hy. originally you get a black plastic behind the headlights, some people fitted some plastic masks round the lamps, but this is not standard, as for oil, i use mobil 15w/40, works just fine, as for gearbox, i used std gbox/diff oil...
what you should check.. hmm... if you want your bis to run happily for some time try this:
-change the plugs, check the plug wires and ignition coil (these rusted away in my case, even though theyre made from copper)
check and set the points if needed
check the thermostat
check the thermo swhitch on the rad-fan
check the brakes, kingpins, tyres...
replace the coolant and brake fluid if old
check and cover any rust you might find...
im running out of ideas, anyway, these are all things i had to fix/replace on my bis after they broken down, so you should check to se if everything is OK.
hope you have fun with your BIS. Gordan [-/