Still available here too from some dealers and from Honda.  That said, as stock runs low, suppliers like Partzilla and others will often substitute the "BR" variant.

In a related note, NGK has discontinued production of the 5k ohm OEM plug caps. Purists might want to stock up...  or if you need a cap might be to time to go non-resistor cap and switch to the resistor plug?

Certain style of plugs have a fixed top so only way is to change the cap for one that fits. Not sure about plug you bought though.

Ok, so I took a closer look at the B8ES plug I purchased from amazon. The amazon item listed it as a B8ES but the actual markings on it say BP8ES and the S looks kind of funny. Maybe a counterfeit? Or does this look right? Also, you guys were correct and I was able to unscrew the top portion of the cap and now it fits into my plug wire no problem.
imgur.com/XtmVGQA

Either way, I decided to swap it out to see if it has any noticeable result. Haven't had a chance to get out and ride at all, so I'll have to wait and update you guys in a couple weeks after I get a chance to try it out.

Here is a vid of it running (relatively cold, not fully warmed up but enough to turn off choke) on the new plug:
imgur.com/JAY0bfA
 

Sounds good. Plugs get a lot of blame when the issue is elsewhere--just saying.

Ring gap?