56 Bird Early or Late

based on that vin, yours is a late car. The problem with "early" vs "late" is that it can change depending on the part. there was not one point where they divide the early or late cars. Changes were made to things at different times. Therefore the early and late is more of a means of identifying the change to a particular part rather than being a change of all the early and late parts. The easiest early/late change to identify is the automatic transmission. The start of production for the 56 cars, the transmission was air cooled. During the production year, the transmissions were water cooled and had cooling lines from the transmission to the radiator. The 55 model year seemed to have more changes. the exhaust ports were changed from a donut to a fluted final. There were differences in the top plate for the soft top, there was also some hammer forming of the hood to stop interference with the radiator, etc. The changes were made at different times, so there is no one date to differentiate between the early and late cars.
I have the same problem with my '57. It's an early build and the engineers were making all kinds of changes while trying to use up leftover '56 parts. Kind of a zombie car. Trying to get it back to as close as original as possible without going overboard. It's a driver so I'm not going for concours points. But have something to point out in local meets. ( haven't done that yet ) .