True. This is the right version. However, you have to build the kernetl-tree that can be used by other pakages. I am trying to install DAHDI, for example (http://downloads.asterisk.org/pub/telephony/dahdi-linux/releases/dahdi-linux-2.6.0.tar.gz
), and it requires this tree. I never built it from the kernel source, and usually, what I've done before is get-apt install linux-headers-$[uname -r].
Going into the kernel and trying to build the header files (by make header_install) creates a directory which is not compatible with what DAHDI requires.
BTW, in /usr/src/ you can find some linux-headers that are not for this image (I managed to get the 2.6.32-219-dove, the -204-dove, but none are working correctly). In lib/modules you will find the right tree, i.e., /18.104.22.168-dove-5.4.2, but it again seems to miss some files, e.g., .build, that is required by DAHDI.
I hope this detailed (and long) message explains... and sorry for the length.