I would like to buy some silver bar or block. I call Ansilee and...

I would like to buy some silver bar or block. I call Ansilee and they told me they have 1kg and 13kg silver bars and blocks. I would like to find out why 1kg bar don't have a series number on the bar but the 13kg bar have the series number. Besides, they told me the mint stamp for the 13kg block is "BHAS" mint stamp with the 999 and the series number on it. Can someone tell me "BHAS" is what company ot mint? I am a new invester last and I only have a perth mint silver and gold bars. IS the "BHAS" a oversea mint or company?

Thank you