Pretty much what it says in the title. My initial reaction is that no, they don't. However the fact that The Three Cords are forged as part of the enchantment, makes me have second thoughts. What do you think?
No. The Cords aren't physical objects. They are only 'forged' metaphorically.
Also: (ArM5, p. 105, bottom of first column)
I see, thanks!
with the *there may be special circustances where this does not apply, which should be attached to any rule in ars magica it seems. For example if you were binding a spirit familiar where making some sort of 'anchor' item (genie lamp for example) made sense it might be a feature of the combination of your virtues and the familiars at the SG's judgement.