Were your able to figure this out.
I don’t think there is a way to directly tell if a new post is being created or an existing post is being updated. If this was a front end form you could use the acf/pre_save_post hook.
On the back end I would probably do something like
– existing posts have a hidden meta value (field name starts with an underscore)
– when my save post function runs test to see if the value is set
– if not then it’s a new post
– before my function is done, set this value so it will test positive the next time the post is saved.
~JH
