I agree that most likely the "non-II" Bambi II's were built before the ones with the "II", but that might not be exact serial number order and it may have differed between the Ohio and California plants.
Airstreams were typically not built in exact serial number order. Serial numbers were assigned as orders came in, but the trailers were built in an often different order for some unknown reason, possibly parts availability.
The lone documented exception to the non-sequential build order I just mentioned is the 1961-63 California Bambis and 1964
California Bambi IIs that were built in serial number order, not the date in which they were ordered by dealers. Possibly this is because the Bambis and Bambi IIs were "no modification" models only built during the winter months, so there was no need to adjust the production schedule for the availability of any model specific parts. In stark contrast, the initial start of 1964
model year production in California was heavily out of serial number order, but that appears to have smoothed out before the production of Bambi IIs began.
We don't have 1964
Ohio production records, nor build dates for the 1961-61 Ohio Bambis, so we have no way of confirming if the Ohio 1961-63 Bambis and 1964 Bambi IIs were also built in exact serial number order, but we might assume that it is possible.
I'd love to learn more details details regarding the use of just "Bambi", "Bambi" and separate "II" and the combined "Bambi II" emblems for Bambi IIs built in both plants should anyone have more photos to post.
P.S. To assist my learning about 1964 Ohio Airstreams for which production records do not exist, do the Ohio Bambi II #2 and #3 serial numbers end in "002" and "003" or "102" and "103". 1964 California SN's started at "001", but there have been unconfirmed suggestions that Ohio might have started at "101".