Whatever bolt and other parts that they are from even a WalMart mountain bike hub, are replacement parts. The Tec9 non sealed bearing assembly is nothing special, which is good and bad. Good that it's a commonly found, inexpensive and easily replaced part. Bad that it isn't the highest end hub on the market. Like you said, regrease it periodically and it lasts longer. Where I bought the bike I have and they sell parts if you want to replace them with identical parts.

http://www.bikepartsmart.com/feature...set-white.html
http://www.bikepartsmart.com/feature...ubs-white.html

http://www.tec9components.com/