I think it might have been IRRenewal who found the answer, not you...
The localizer frequency is indeed common to both runways, but the equipment is not - they just turn the one associated with the active runway on at any given time.
If the localizer frequency is common to both runways, so will the DME and glideslope frequencies. DME & GS are frequency paired with the localiser so a particular localiser frequency will always use one particular DME frequency and one particular GS frequency. But although there will only be one DME antenna, there will be two separate GS antenna arrays, one pointing each way.