Enobaham,
I am not sure what you would find silly about it as there is a reason they have multiple keymap types to begin with. Just because the devices look similar doesn't mean that they are the same.
The 5320 only has one page and the 5330 has 3 pages; how did you think that would work? You can absolutely assign a 5330 keymap to a 5320, but don't expect it to look the same or for that matter work the same. The top 3 keys on the 5320 don't have lights in them so you typically don't want to use keys that provide an indicator.
If you want the 5320 to have 2 pages then you have to create 2 separate 5320 keymaps and have one as the Standard Keymap and one as the Alternate Keymap; then put a key on their phone to move to the alternate keymap.
Thanks,
TE