I was curious to know particularly if the firing control group and gas tube matter when building an AK-47 from a pre-cut receiver. For example, would I be able to take Romanian and Egyptian parts and interchange them? Or is it better to have your parts be from the same country even if the numbers don't match with the parts? I'm disregarding furniture and mainly focusing on the bare bones working parts. This would be for a fixed stock rifle probably built off a Nodak receiver. I was trying to Google this and didn't find any solid leads. Thanks in advance.