How do you (Can you) roll back an Exchange 2010 rollup

One of my admins applied SP3 rollup 3 ahead of the cas server that proxies all inbound connections and now they can't access OWA or activesync from the external url. I cannot apply this rollup to the CAS server until next week. I have copied the resource directory (14.3.158.1) to the CAS server and performed an IISReset, but the users still cannot get connected through the external URL. All other remote exchange server users are working fine. The error produced is as follows:

Client Access server "https://mail.blahblaw.com/owa", running Exchange version "14.3.123.3",  is proxying Outlook Web App traffic to Client Access server "someplace.blahblah.com", which runs Exchange version "14.3.158.1". To ensure reliable interoperability, the proxying Client Access server needs to be running a newer version of Exchange than the Client Access server it is proxying to. If the proxying Client Access server is running a newer version of Exchange than the Client Access server it is proxying to, the proxying Client Access server needs to have an Outlook Web App resource folder (for example, "<Exchange Server installation path>)\ClientAccess\owa\8.0.498.0" that contains all the same versioned resource files as the Client Access server it is proxying to. If you will be running Outlook Web App proxying with mismatched server versions, you can manually copy this resource folder to the proxying Client Access server. After you copy this resource folder to the proxying Client Access server, you need to restart IIS before proxying will work.

As I said, I did try the recommended fix. So I would just like to know if I can roll back SP3 Rollup 3 to just SP3 and if so, how?