It looks pretty much identical to mine which I believe is a (late) 1993.
I have a catalogue from 1993 that is different to the one posted on RB which I suspect is from early 1993 (or is a Europe only catalogue?). This alternate (North America only?) catalogue shows models from the Cinder Cone and up with front suspension. This suggests some time in 1993 they made the switch to suspension corrected frames and produced another catalogue (different model colours too). I also have a price list that states "1993 1/2".
Regarding the Hei Hei, my bike, the one in the ad above and the one in the (late) 1993 catalogue look like the 1994 frames but have the 1993 decals. They have the lines through the main down tube decal, the bullet drop outs, no canti bridge and a "dog collar" style cable guide.
Mine is a 17" and the top tube measures 20.75" c to c. The catalogue states 22" which is correct for end to end. The 18" states 22.5" end to end.
I hope this info helps. If anyone wants me to send them a pdf of the alternate 1993 catalogue send me a PM as I have a hard time posting photos to this site.
If you view the last two pages of the Kona Titanium Serial Number List thread, you can read a little more information on this frame - story starts Sun Jun 28, but is interspersed with the discovery of the first 21" Hei Hei that we know of. There is also reference to how Kona quote Virtual or Effective Top Tube length in the catalogue, while it is easier to establish Actual Top Tube length Centre to Centre on a bare frame: