This armrest was sold in Europe as part of a cell phone kit for MK4 cars. It is identical in style to Audi armrests of the same era, but the mounting bracket is different.

I believe the part numbers are:
3B0867174 – Bottom
3B0867173A – Lid
4B0862413A – Telephone Lift

There may be multiple color codes.

There is also an Audi LED kit that fits inside the armrest and illuminates the interior with a red light:
8E0971196 – LED Kit