Yes, it is the 320EX. There are several limitations to it relative to the 430EX II.
1. 320EX has a manual flash zoom with just two focal lengths: 24mm & 50mm. 430EX has auto flash zoom with focal lengths from 24-105 mm, so it will be much more powerful with telephotos greater than 50 mm.
2. The constant lighting for video on the 320EX is very weak and only useful at fairly close range according to reviews. The 430EXII, of course, does not have this light at all.
3. As Jon says, 430EXII is more powerful in general, although it is by a small amount in the 24-50 mm range.
These differences are important to me, so I will be buying a second 430EX II soon. If these differences aren't important to you, the 320EX is less expensive and a good buy. Both 430EX II and 320EX can be used as wireless slaves using ETTL in the Canon system. If I ever get a third flash just for backgrounds, it could well be a 320EX.