I bought a second-hand table saw with what I am told is a 78-100 fence system. My problem is I can't tell which rail part is appropriate for my system, because the rail measurement (48 inches long) doesn't match any of the model numbers on the manual (BHS28, BHS40 and BHS52) that came with the system. The guide tube is 58 inches long, so I would guess I have the BHS52, making the 52L12 rail the correct one. Is that right?