Exact reasons why I went direct to Koyo Australia technical. They gave me the brand and grade of grease used, and all it's specs. To buy a tub of that grease was about three or four times price of normal bearing brand name grease 500gram tub !
decades ago, there were concerns that the bearings were just coated to prevent rust and NEEDED to be properly re-packed.
can't remember if that was disproved or not. try a search on the topic? (man I'm getting old)