I would say its a G. The 1967 Kennedy halves are 40% silver however, and as of today it is about $4.15 in silver. It is also not a rare date and is pretty much worth the same uncirculated as it is in any other grade.
Low-grade coins? That's a silly, silly thing to collect (at least in my opinion). Wear is any more and you won't even know what it is besides a hald dollar! But if you like that sort of thing, to each his own!
Lowball coins are kinda popular. I know Bill Fivaz (author of the cherry pickers guide) collects them now and I met someone at a coin show who had the first P01 peace dollar. He was very proud of this and had the coin on display and wouldn't even think of selling.
From what I understand from reading the lowball thread is that some coins such as the one pictured were never really largely in circulation. So most examples are in high grades. So if you have a poor circulated one, you have a rare coin.