I do have an OS 3320. The 448 BH that I have currently has part #LVB25614 on the attachment part. I also have the mounting plates LVB25568 for a 4x20 series. My conclusion is that LVB25614 is the attachment kit for the 4000 series. My dealer agrees with this.
I see the 448 BH in the ebay link above has been sold for in my opinion a low price.
I see the 448 BH in the ebay link above has been sold for in my opinion a low price.