https://www.tamiya.com/english/rc/manuals.htm
You can find manuals for some of the trucks here. They show drawings of the frames so you can compare hole locations. Usually the groups of holes are similar, but spaced differently depending on length of the truck and type of cab. If you want to make custom length frames, you can use 3mm + 2.5mm drill bits and an M3 tap and an original set of frames as a guide.