The “-gcdddc52” would be a git repository checksum. This is applied to 3.10.67. What the difference is between that git version and the downloadable L4T version I do not know. You would be safest downloading from the link you mentioned above. Search for “Kernel sources”.
The driver package is the flash program and everything you need for basic flash, except for the sample rootfs. Kernel changes when u-boot is the boot loader (and in JTX1 it is) do not require flash to update.
The JTX1 ships with the same configuration as kernel target “make tegra21_defconfig”. This also matches the running default kernel output in /proc/config.gz. With CONFIG_LOCALVERSION set to “-gcdddc52” to match the suffix of “uname -r”, this becomes an exact match. Alter swap to be enabled, and you’re ready to go. Because swap is built integrated into the kernel, and is not available as a module, I’d advise altering the CONFIG_LOCALVERSION suffix to something like “-gcdddc52_1” and populating a new module directory.
My advice summary on this: Build the kernel with “-gcdddc52_1”, copy the completed Image (and if you want, zImage) to JTX1 /boot/ as “Image-3.10.67-gcdddc52_1”; create “/lib/modules/3.10.67-gcdddc52_1”; recursively copy “/lib/modules/3.10.67-gcdddc52/extra/” to “/lib/modules/3.10.67-gcdddc52_1/extra/”; install all of the new modules to “/lib/modules/3.10.-gcdddc52_1/”, and then add or edit an entry in /boot/extlinux/extlinux.conf while leaving the old “/boot/Image” entry as a rescue entry. Serial console will let you select which entry to boot, so you don’t have to hard code while testing.