It depends if the crank you have bought has original bearings or if they have been changed for a "compatible" bearing at any time - although Campagnolo used a proprietory bearing dimension (6 mm wide not 7 mm), there are companies out there that market "compatible" alternatives.

If the bearings are original, there is no seal to the inside so we'd recommend packing the cups with grease before (re)assembly in order that the grease acts as force-lubrication as you tighten the main bolt and as an additional seal (the external side is sealed and has a lip-seal fitted against the cup and there are two wiper-seals in the base of the cups that contact the axle).

Greases can generally be mixed in these types of application with no problem but if you want what was marketed by Campagnolo as Campagnolo-LB100, it's made by Kluber and is Topas NB52 - it's freely available as it's widely used in marine and snomobile applications as well as in other precision engineering applications.