I remember some instructions when i put new gabriel shocks in my astra, it said on there 10cl, which works out at 100ml, which is allot of liquid. Too much to fit in the strut with the cartridge too, the actual quantity should 10ml. The shocks were made in south africa so some kinda mismatch in scales there. When i put in the billsteins the instructions said 10ml.
I dont see any bad effects of it being full except maybe over time the oil could penetrate the ring nut and maybe vibrate undone. If this happened your car and spring would part company i'm afraid.