3rd ed Warhammer Armies (1991) had Kislev infantry among Old Worlder Allies and Kislev Druzhina among Old Worlder Mercenaries.
The illustrations showed basically Vikings. Overall the Kislevites seem to have been 10-12th century Russians/Eastern Europeans instead of the 15-16th century Russians/Eastern Europeans they became with the 4th ed Empire book & models. Clearly, you were supposed to use models from the Viking/Tribesmen/Fighters ranges.
-Z