Man, you've created so much confusion. I think you got confused yourself
First of all, The two sources you've given contradict each other...
The first source reinforces what you've said about the NATO designations and gives the 9K310 system and its missile 9M313 the NATO designation SA-18 Grouse and claims that it is the newer, more capable system. In other words, the 9K310 Igla-1 system is the "proper" Igla, and the 9K38 Igla system is the stop-gap measure.
Your second source confirms the, in your opinion, common misconception.
The SA-16 is a variant of the Igla (SA-18)
design. Because of delays in the Igla program,
the Igla-1 with a simpler and slightly less
capable seeker was rushed into production and
fielded 2 years prior to its progenitor...
Even if we'd assume that you and your first source are right it still wouldn't make sense, because the game itself disagrees with this notion.
CMANO gives the 9K310 [Igla-1] system and its missile 9M313 the NATO designation SA-16 Gimlet and it is, in game, the less capable system with Single Spectral IR Technology. Despite this CMANO still claims that this less capable version of the Igla was first available in 1988. That is, after the other Igla we're discussing here.
CMANO gives the 9K38 [Igla] system and its missile 9M39 the NATO designation SA-18 Grouse and it is, in game, the more advanced, more capable system with Dual Spectral IR Technology. Despite this CMANO still claims that this more capable version of the Igla was first available, before Igla-1, in 1984.
Something is wrong here either way. Either the naming is wrong and mixed up or the years of introduction are wrong, or the technology is completely wrong.
"Nuclear weapons might be the currency of peace... but what a terrible price..."