12880299 would only be applicable to your database Oracle Home. It was only released for 10.2 and above, and I can find no article that discusses it in relation to EBS/R12, so you would not have to apply it to the appTier.
I am not sure what version you are on, but the latest technology patch list for 12.2 is in the following doc:
Oracle E-Business Suite Release 12.2: Consolidated List of Patches and Technology Bug Fixes (Doc ID 1594274.1)
The latest April 2017 Critical Patch Update doc has all of consolidated security patches required for EBS.
Oracle E-Business Suite Release 12 Critical Patch Update Knowledge Document (April 2017) (Doc ID 2241313.1)