New to the forum and need some help with terminology

[Scott Garner]

Hello all,

I recently purchased a Parker (SN: 10275) at a local estate sale. This gun might just end up being wall decor.

I've been involved with shooting sporting clays and other various shotgun sports for years but this is my first venture with a SxS.

I an filling out the form for a research letter and had some questions...

What I do know:
Mfg Yr: 1878
Lifter Action
Splinter Forend
Twist Damascus Barrels (12ga... Measure aprox 30.5")

What I don't know:
What is the difference between a round and ball grip?
What the heck is a DHBP Butt type?

I have included pics and any help would be greatly appreciated!

-Scott