Zinc is pretty much borged to mame. Any new enhancements goes straight to mame and no longer zinc.
wrong again
There is a final version planned.... the hold up is the decryption of the zinc roms as the hardware protection has finally been broken. (It was fudged in zinc before)
Unfortunately this means all of the zinc roms have to be re-dumped, which means that the guru has to get ahold of the boards again and re-dump them.
Some will, however, appear in mame first as the zinc team wishes to wait until all the redumping is complete before releasing the final version. The mame team working on zn emulation (which are basically the same guys) are adding the new roms as they go, causing a few of the newly dumped roms to work in mame right off the bat. They won't work on "fixing" the emulation until all the dumps are complete though, just like in zinc.
Be patient as the zinc team is temperamental and bothering them could result in canceling the final release.