The "V" numbers you see here, like "V27" are the release number of the update CD. An update CD may or may not have changes for any particular NAV model. In particular, there haven't been any updates to the MK III CD NAV for some time.

I can't say if you'll see any improvement because I don't know what software you had before the update (it may have been older than the 3-1/63 you now have).