I'd have thought more likely the 'wobble blob' strut top has let go, I mentioned this briefly in my rebuild thread (along with why I call it a wobble blob

), but since the strut top mount's basically a big bit of rubber which isn't attached to the car it'll be more prone to wear than a traditional strut top, and fitting uprated springs will increase wear since it'll be absorbing more force from bumps in the road than usual.
Should be simple enough to see if a spring's let go but I wouldn't mind betting you'll soon be cursing at the corroded strut bolts whilst preparing to fit a new £30 lump of rubber.
The Euro-spec 500's wobble blob: