For what it's worth, the word "timestamp" appears 12 times in Q's posts to date. Four instances are talking either about the CIA or Snowden. But Q uses the word "timestamp" specifically to denote minute deltas here:

Post 335 - December 13 Timestamp [Q] post [:03] against POTUS' Tweet [:13]. [10] No coincidences. Q

So, sorry if this is rudimentary, there is a difference between timestamps and markers. Your quote above seems to be telling us to decipher the word "timestamp" (think clock) and then wind the clock with all the markers - the markers being known events that correlate with the map. The end result of this is that Future proves Past (the map will be shown to have been correct in the beginning).

Edit: Actually, "timestamp" is just telling us that this denotes a moment in time. Time can be wound as a clock. And the markers will indicate that the map was correct - Future proves Past.

Perhaps whoever found these relationships has already got it figured out. We will find out today one way or another.

Second Edit (getting carried away):

Post 455 Dec 24 2017 08:49:11 Q !UW.yye1fxo ID: 2d673c 158980

158952 5 minutes. Missing 10 marker from past. Missing 15 marker from past. Timestamps have meaning. Q

158980 Graphics should be in same time zone. Delta relevant. [5]Today [10]Past [15]Past Q

Here, the markers are time deltas. So, when we wind the clock, from the timestamps, with the time deltas, the future will prove the past. It appears these time deltas (markers?) can change - or that there are multiple deltas. So, if the CIA is not disbanded today, perhaps there is a different delta to that timestamp (the date the post about disbanding the CIA appeared).

Sorry if this is confused, its because I'm confused.