LCD will not close into bottom lock.

bought used PowerBook. lady said will not close. thought it was hindges. tore apart and looks great. the top is just a little off from the bottom part. wondering if previous owner changed the top portion with another PowerBook 17 model that is just slightly different from my model. Question, are all PowerBook 17 tops the same size and interchangable to any model of PowerBook 17 so that they all lock into place. mine looks like the top is overhanging abit so that its just a few millimeters off from locking into place. It looks solid with no play or wear, just a little off but cant push or force it into the locking tabs. magnets fine, claps retrack but just misses the hole. thanks