Bigroby, generally it is to say, that EICKHORN has been a very prolific producer who "normally" did produce all parts in house. But we do know also very well that sometimes, when they ran out of certain parts, especially against the end of the dagger production, they have bought/used parts of other firms, mainly WKC, H�RSTER or socalled "generic" parts.
ALCOSO is not known as a firm with which EICKHORN did have a close cooperation.
Concerning your dagger: A comparatively middle/late ALCOSO pommel on a more early EICKHORN dagger is not something we would expect to see. Due to the even look, the perfect fit and the even patination it does look to me that these parts are together for a very long period. We will never know for sure when the pommel has been attached. Some collectors would say "it is not textbook" (I personally do hate this expression). I for myself do like the mentioned even, patinated look. The fact that it is out of the normaal region of EICKHORN armies (even out of those with better known spare parts like the above mentioned, eg. generic) in case of reselling it is not as easy to sell than a pure EICKHORN.
Regards,

wotan, gd.c-b#105

"Never look for sqare eggs" as a late owner of an original FHH-dagger used to say.