UPDATE: G IH A NI ID II on the official MW3 forums was asked when can PC players expect Collection 1, and he was kind enough to answer:
“The PC will receive a patch preparing for the arrival of DLC Collection 1 likely tonight at 2am PST. Collection 1 is well into its test cycle on PC. I’ll see if I can get an accurate ETA for you.”
According to a Russian retailer, the MW3 Collection 1 is slated for release in “April 2012”. Infinity Ward has confirmed that PS3 Collection 1 is coming 4/19, but only said “coming soon” to PC.
Currently, we’re a little skeptical about this specific site because it states MW3 Collection 1 is 1.53 MB (It should be a LOT more than that). Now this does not mean that April 2012 is wrong, it just seems their description or file size seem a bit inaccurate.
We will update if we get an official confirmation from Activision/IW.