C5 Mk1 2001-04 Front Brake Calliper Guide pins

[aspire_helen]

The calliper slides on a pair of guide pins which locate into bores on the calliper yoke (or carrier). Replacement pins are readily available. However the 2 pins are different; one has a rubber sheath/insert partway down its shaft, the other does not. This is also reflected on Citroen's parts diagram. BUT, I can find no guidance on which pin should fit into which bore, top or bottom. Haynes completely omits inspection of the guide pins. I ask because my lower guide pin seized in the bore and took a lot of effort to extract it. It had the rubber sheath on it, somewhat mangled by the extraction process. Indeed, it was not the rust per se which made extraction difficult, but the rubber sheath jammed into the rusted bore.
Which pin (sheath or no sheath) should go into which bore (top or bottom)?
Ta very much!