a few more points
your car looks like it is in very good shape!!
the rear turn lens in red is very early and no longer made also the front turn lens are also early -- I did not think that they had the small turns and the side lights -- normally they had the larger front turns on cars with the sids
The bulb watts should be marked on the bulb frame (is it metal or plastic) the 21w will be fine -- use blubs with silver not brass ends and you will be fine.
The front turn also has the small parking bulb.
many 108's do not have the right mirror -- it looks like your car has the later style driver mirror with the larger base.
I normally keep my Rad filled almost to the top -- I have the manual and I think that this is correct -- the system does expand and does not have any place for the water to go - just out the tube
The heaters on the 108's work very well -- the upper left is blower speed -- 3 settings for the fan -- first the flap opens allowing you to use air pressure to bring in air at highway speed and then the fan speeds the more you move the lever.
upper is flap for heat/ defrost
The lower two are heat for each side - they work flaps as well as the heater valve - this valve is located on the heater matrix