I believe that due to mil using engines of a different mark to the civy ones you will NOT get your Gaz on a C of A unless you obtain a civil certified Astazou (3N?). Mil engines are not certificated, and there are either no civvy Astazous left, or if available cost more than the machine is worth (£100K or so!!!)
Last I heard ex Mil Gazelles are destined for Permit to Fly only. Hope I'm wrong!
Anyway, the Gaz is a lousy commercial or charter machine, noisy, cramped & crude inside and desperately expensive to run, DOC said to be same as Twin Squirrel - 'nuff said?