I have two pairs of KP-250's that are different than any I have had before. They have a cloth on masonite grille cover, K-42-K woofers instead of KP-42-KP's and a build date QA tag from 1989. The only information I can find from Klipsch talks about 2000 to 2004 for KP-250 builds. These are far more musical than the later KP-250's I have had. Does anyone have information on these?