Step side wood bed question

[mikeshome]

The 64 step side i just bought has a piece of checker plate instead of wood. All the cross frame is there ,We are planning to put wood kit back in. Question is on the box sides is angle iron (think original ) .Does the narrow outside wood sit on this then the polished chrome angle goes on top or does that need to be removed ?Have done fleet side but never step side .No holes in angle that is there now. Thanks in advance. Do not have pics of box at this moment.