That could be it, actually. On the cheaper BC rich models, I've noticed a fair few of reviews commenting on how their knobs fell off. For example, two reviewers say so here:
http://www.musiciansfriend.com/product/B.C.-Rich-Metal-Master-Pack?sku=511201
Granted, its a different guitar but it might have the same knob and pot combination being from BC rich also. So, maybe the previous owner's knobs fell off and they decided to superglue them in.