I have a pair of Tie Rods salvaged from a No. 4. The Bottom Frame Assy drawing denotes the Front Tie Rod as p/n MR-104 and the Rear Tie Rod as p/n MR-105; the Front one appears longer. The two parts I have are identical, with the length being 21-7/8″. On my own No. 4, the front rod measures 22-1/2″ and the rear 21-1/8″. Why the differences, and does any of this matter?