@Punkawallah
Here is the Oil Paint filter from CS6
https://dl.dropboxusercontent.com/u/23953768/Oil Paint.8bf
Click on that, download it.
I'm not sure if this will work, as third party plug-ins are platform specific, but as this is the actual .8BF file from CS6 it may well work on a Mac.
Locate where the filters for your system are located. On a PC it's C:\Program Files\Adobe\Photoshop CC (64bit)\required\plugins\filters
On a Mac I'm not sure, but probably applications > photoshop folder > plugins > filters
It may have the "required" folder also on a mac, so check in there if that is the case. You'll know you're in the right place when you see all the filters as .8bf files. Usually the system installed filters are in a different place to third party ones, so you're looking for where teh system defaut ones are... so you're looking for these...
If you can find the equivalent folder on a Mac... that's where it lives.
Once it's in the right place, restart PS. It works here on the PC... Oil Paint is now back in my filter list on CC, so it should work on a mac.
Give that a go.... although I've no idea why anyone wants to use the hateful thing.