Gentlemen, I am desirous to own a Rapide or Shadow, but get somewhat confused. The magic '1,900' between engine and upper/lower frame seems irregular? There are three examples that I have come across (two in Canada) and (one in USA) where each B Rapide holds a HRD Works Order Form yet shows a variation numbering outside of the 1,900. Eg. Two bikes both 1947 'B' Rapides (E: 328, Frame 2327) & 1947 B-Rapide (Engine 350, Frame: 2349) yet both have the Vincent HRD Works Order Form. What is interesting both have a variation of 22 between them! Is it fair to say that the general rule is the 1,900 but there were occasional miss numbering? Is the key then the Works Order Form in alignment with the bike's numbers?. Any insight/guidance? I do not want to purchase a Vincent with is not original. Thank you!!