A few things on the stamp history don't make much sense, so trying to understand, I went ahead and listed all the stamps from CP Archives and sorted their ID from lowest to biggest, in hopes they'd be in release order. By doing so, I took some notes (very big text so I didn't have time to look up for grammar mistakes, but it should be readable, also I wrote that before I editted the Stamps page, so what you see now on the page is after my edit and this text is from before it):
-The history mentions two new stamps released on the mountain expedition, and since it does not name them, I wasn't capable of finding which ones. Taking a look at the IDs, the first stamps that come after the 107th stamp (there were 107 stamps released at first), was the Game Day! stamps, followed by the Puffle Rescue Stamps, which are then followed by the Missions, which then are followed by two party stamps, Happy Room and Party Puzzle, which were released on July 26th and would then match up the story. This would make sense because Happy Room's ID is of 182 and the last stamp for Missions' ID is Snow Globe (180). So they likely predicted the amount of stamps they'd use when releasing Happy Room, but why did they miss out on ID 181? Well later it would also be answered that Puffle Rescue was intended to have 28 stamps instead of 27, so that explains the gap.
-Coming straight up from the previous one, since they were able to predict what would Happy Room's ID need to be so it would be exactly one after the game stamps, it was obvious that they had been planning the Puffle Rescue, Missions and Game Day stamps ever since stamps were initially released, or at least shortly after they were, up to the point they even created Game Day's stamps first (you can check by looking their IDs, Game Day's first stamp ID is 115 while Puffle Rescue's first stamp ID comes on 130). There might have also been a cancelled Game Day stamp due to the fact Goaliee, the last Game Day stamp's ID is 128, while SOS 30, the first PR stamp's ID is 130, but they might have miscounted or purposefully chose 130, or this could be referencing to the stamp that was removed soon after, as stated on this section:
"On August 13, 2010, a new section called "Console" appeared after "Games". It contained a sub-section named "Wii" with 1 stamp. It was removed soon after.".
TL;DR Game Day! stamps were likely made before Missions and Puffle Rescue's despite taking a while to release, and they were all being planned shortly after stamps were released.
-Taking a slightly further look at the IDs, it was also revealed that a bunch of the stamps released on October were planned before the Field OPS stamps, and the same would happen for more stamps later on. I guess it's interesting to see how the devs were planning the stamps to begin with, but at this point the IDs couldn't realy help me that much anymore.
-Despite unclear, everything was going fine and ok until I came across this:
"On December 16, 2010, 2 new stamps were added which were the Volunteer stamp and the Top Volunteer stamp for the Holiday Party 2010. This brought the total to 229 stamps.
On April 26, 2011, Pizzatron 3000 and Ice Fishing stamps were added.
On February 3, 2011, 2 new stamps were added which were the stamps from the game System Defender. This brought the total to 242 stamps.
On April 25, 2011 new stamps were released for Pizzatron 3000 and Ice Fishing."
It was clear that this was just a writing mistake as it made no sense, so I searched up and aparently System Defender stamps were released on January 14 of 2011, and Track Herbert was added later on the year on August 18, and according to the wiki itself, the stamps were released on the 26th, so this solves this little issue.
-Finally, I just noticed a sequence of unlisted stamps, which messed up the counting order, the thing is, I was able to organize every stamp, with the exception of one, so if you add up all the one I've listed on the history, it will add up to only 351. There are also some other inaccuracies, such as, I've searched that System Defender only had 10 stamps upon its release, so there are other things that need to be fixed.
EDIT: The list is now complete, the only thing left is to add the correct date for each stamp (100% sure the current dates are not all correct)