Yes, Wolf does make 154gr. SP's in 7.62x39. I don't know if it's necessarily more accurate, but it is definitely harder-hitting (out to a certain range, at least) than the other two 7.62 rounds they offer. It's definitely geared more towards hunting, but I would venture to say that it's probably not very effective or humane past 200-250 yards, max. I love Wolf, it's great for plinking, but it's not terribly accurate. It's not like it's Hour of Angle or anything, but it's just not as accurate as some of the domestic ammo, or even Sellier and Bellot (also cheap and good, plus they use brass cases instead of laquered steel if that matters to you.) For plinking, Wolf is fine and the majority of the problems it has is in American weapons, which are not designed to work with laquered ammo (pretty much all Russian and "commie" guns are designed with laquered ammo in mind, and eat it without question.)
I know a lot of people that have used SKS's for hunting and they work great for it. However, there's two things to keep in mind: SKS's are battle rifles and as such, were meant with relatively close combat in mind, so their effective range isn't as good as a bolt action. Second, many states do not allow hunting with a semi-auto rifle, so it's wise to check beforehand. But they make great truck guns, and they're pretty indestructable as most Soviet guns tend to be.
I'd be careful about using the rifle for home defense, mainly because they can be a bit powerful. The 154gr may be a good choice because it's going to have a much lower velocity than the FMJ or HP 122gr. rounds. If you live in an apartment, be especially aware of the adjoining units and how to potentially avoid firing in their direction if possible. I've shot through several layers of 2x4 with an SKS from quite a distance, and it went through all of them without a problem. The 7.62 round is pretty mean, and I like it a lot more than .223 for antipersonnel..er, umm "homeland defense" uses.
The SKS is a fun rifle, especially for the money. Just watch out for flying brass, they were designed to shoot brass 30 feet straight up, and firing from the hip can cause all manner of head trauma if you're not careful.