The $69.95 round receiver guns and $79.95 hex receiver guns are pretty much the same. The difference is the receiver ring (round vs. octagonal, respectively) and the Hex's were made through the mid-30's (rounds were made mid-30's till the mid-40's). They have the same type of wood stock (beech?).
The laminate stock guns can be either "round" or "hex" but they have laminated wood stocks. They are slightly less common which is why they're going for $20-$30 more.