RE: Do not Allow Posting Acquistion Cost for the second time.
As rightly suggested by the community expert Bilal, this may not available as a standard setting as there are valid business use cases wherein the user needs to process acquisition cost on a FA in broken down entries. These acquisition entries are nothing more than Journal entries
However, if you are willing to spend a couple of hours, a small customization will solve your issue, in which:
1) If a FA has the field "Acquired" already marked TRUE, an error will pop up if an Acquisition is processed against the FA