Are you looking at generic feet or Viking feet? The 630 is in the Optima group (group 3) of Viking machines. Bernina sells feet with 'old style' or 'new style' designations because they changed the mounting mechanism (not the shank height really) but left the foot numbers the same. To my knowledge, Viking does not refer to them that way, but generic places might. Not much help, sorry.
You can find any Viking accessory or part number on their website. That may help.
http://www.husqvarnaviking.com/us/ac...ies_search.asp