Some taps come with 'flexible ends' already sweated on - in either copper or (as in your case) some other material, to enable the end of the tap unit to be fitted onto the 'supply' pipe (which is often copper, though these days not always). Equally, taps terminating in only a threaded end are often separately fitted with a short length of flexy pipe on installation by the fitter to make the whole lineing-up of the installation easier.
So your installation could be either, and (I suppose the insurance company) in the former case will argue you are not covered by insurance and in the latter case you are.
If you can crane your head in under there, you should be able to see whether there is a compression joint (with a pair of nuts) between tap and flexible pipe or not - just where the tap emerges from the underside of the basin (I'm not talking about the big nut which tightens the whole tap assembly onto the basin - that will always be there).