We have all seen the engine for Simourgh which is a combo of four Scud missile engines. But what information do we have that prompts you to say that the N. Korean version is the exact engine?
The Simorgh first stage is powered by four Nodong/Shahab-3 engines, which were designed by Isayev (Russian) in the 1950s. They are twice as powerful as the Scud (Isayev S5.) engine. Each Shahab-3 engine produces 28.3 tons of thrust at sea level, and 31.6 tons in vacuum; I can provide more details if necessary, as I the engineers in Russia familiar with thee engine's origins and technical parameters. And while Iran's engineers are very capable, they do not have the technical wherewithal to enhance this engine to generate the thrust values quoted by officials. If they had such capabilities, they would have also designed one large turbopump to feed the four engines; in the mock up unveiled in February 2010, each engine was supplied with its own pump.
Having said this, it will be quite a feat if the Simorgh is launched successfully.
Of most interest will be the make-up of the second stage. Will it be similar to that used on Safir, powered by the steering engines from the Russian R-27 (or other Makayev design bureau missile), or will it use an R-27 itself, as North Korea did with the Unha-2? If the latter, Iran will have a powerful satellite launcher, and a possible basis for a long-range missile with the capacity to target all of Europe if developed and fielded as a ballistic missile. The latter would also confirm the Wikileaked diplomatic cable that quoted American officials telling their Russia counterparts that Iran had received the "BM-25" which is based on the R-27, and was seen in a North Korean parade in October 2010. US officials call the North Korean version of the missile, "Musudan".
Doubt is not a pleasant condition, but certainty is absurd.