You can access the pivot on a stainless handled knife? I dont own an Endura but I'v never seen an SS spyderco that had screws in it.
to the OP: I'v never tried it but I have herd or others putting pieces of wood on both sides of the knife put the pivot area in a vice and apply LIGHT pressure. this should move the scales down on the pins slightly tightening the knife and removing any side to side (lateral) blade play. Just make sure to use VERY little pressure in the vice.
Hope this helps.