Originally posted by ScooterMaxi Jim Adam corrected me. If the lens is DA L (plastic mounting ring), you do have the newer optical design; apparently Pentax decided not to include the II designation on those lenses that went out with the K-X because the "DA L" is enough of a designation. Of course, the WR is a pretty big deal - worth getting on any WR body. All told there are 5 versions of the 18-55, and four of them are the new design! If it has "DA L" or "WR" in the name - it is the new design (and of course the "II" as well).
And I thought Shimano and all their mtb and road hardware naming antics was bad. At least Shimano put the exact model number somewhere on the part. The fun part was finding where they put it. You'd never think they could make writing that small on a part
Pentax..............well, they just give you a lens and say "go." It could have some distinctive writing on it, or maybe not