While importing via courier/shipping services, the chances of inspection are higher (about 50%), and you will be asked to produce a letter from the Qatar Scientific Club.

It may take you couple of visits to the club to get it, but nothing too cumbersome.

You may want to purchase the model in Doha itself though :

http://rcqatar.com/rc-in-qatar/hobby-shops-in-qatar/

In addition to the ones listed above, you may also find some models in the "Expo Center" store in the City Center Mall.