LH toe board extensions

Trying to cut mine out, but it, and the torque box is so rusted I can't really see what I'm doing.. DOes the toe board sit on top of the torque box (as in, sheet metal on sheetmetal), or is the top of the torque box open, so the floorpan extension MAKES the top of the torque box? I bought some extensions off ebay, and they look to be of horrible quality (metal is way to thick, and seems to have been bent in someones garage with a press.. Dimensions are not identical at all.. Any suggestions? Thanks