No, because as Coulson said it, the Triskelion shouldn't be even a thing in 1983, because it was built in 1989, they come from 2019 of the MCU timeline and now they are in a new one, they will find a way to return to the MCU in the finale, but not everybody will.
Ah, I see you've misunderstood my silly theory. In the timeline Coulson comes from, (which may indeed be the original MCU timeline, but let's imagine for a moment that it's not) the Triskelion was indeed under construction in 1989 as per what we saw in Ant Man. (The movie doesn't actually say when construction was finished, BTW.)
In the new timeline created by Chromicon interference, the Triskelion was constructed by and destroyed in 1983/84. I'm just saying that there's no on-screen statement in Ant Man that says something like "this building we're standing in is being built to replace the Triskelion that was destroyed a couple of years ago under mysterious circumstances, we never actually found out what happened with that (and we may or may not suspect aliens, that's kind of up for debate) but we covered it up anyway because we're a secret organization". Under this theory, the Ant Man Triskelion is being built to replace the building that was destroyed in an attack that SHIELD may or may not realize is extraterrestrial.
So it's just possible (unlikely, but possible) that if the
new timeline is actually the MCU as we know it, AoS is introducing the slight retcon that the Triskelion construction in Ant Man was occurring
because of the Chronicom's attack. Coulson's statement that the Triskelion was operational earlier than in his home timeline was correct from his PoV, but also a clever red herring by the writers playing on our assumptions of what we know of MCU history in order to misdirect us from the fact that we are now in the main MCU timeline. The pre-existence of Project Insight is effectively nullified because the Chronicom attack wiped out most of 1983-era SHIELD's records and resources (while sparing Stark, Carter, Pym, etc.) so Fury or whomever is free to come up with the idea on his own. (As indeed he did in the original, non-MCU timeline.)
Is this absurd and convoluted? You bet, and extremely unlikely to boot, but rest assured I did take all available information into account.
Excited to see what happens next week.