I bought a oc3-42 today,It had a few parts that I needed for my hg68.It has the factory underdrive transmission,the engine is lose &amp; The serial # is 1WHO20,does this make it the 20th oc3 built?I am not sure if I want to restore it, All of the undercarrage is gone.I have a full plate with this hg68,But I hate to tear into this oc3 for the parts I need, if it is one of the first oc3's built.Are there any oc3's with a lower # than this?