are you sure of that? (for example i dont think there is GNV version in 1999) What are your sources. Samand (since 2003) isn't accept because of copyright on pictures (and notother engines)?

I used Iran Khodro's website and Wikipedia, but did not find information for the CNG model, but it is almost exactly the same engine as the normal 1.8 so I guessed it was introduced at the same time, but maybe I am wrong.
The 2003 Samand picture came from Iran Khodro's site just like the other pictures, so they are official.

Persian name: پژو پارس (Pajo Pars)