original to the first owner, the 2nd, 3rd, 4th, or to you? for starters, the Assembly Manual is a 1955 document [pages are all dated], no telling what changed by 58/9 - unless you can document "original" and have the maintenance history of the last 60 years, no point in creating mysteries .... a Roch B carb is a Roch B, and any PO may have felt the need for the optional oil bath air cleaner
Bill
