I do not have the full version but did get an upgrade to the version I have. Based on that it appears the new expansion pack would not work in Rapture for two reasons. The samples are not wave files and the program files are not compatible with Rapture 1.2.2. You would have to convert the samples to waves and build your own programs.
There is a free expansion pack for DPro which I believe was the seed for the Gibson Bass Collection. Remember RPro replaced both Rapture and DPro. It is still available
here. There are instructions on installing it in DPro and DLE.