It's true as 0f 8-12-15. Check it yourself with the URL address bar.

<-- FIRST MEME SHARED ON IMGFLIP?

As of 13/8/15, I can only find up to 14354 "Latest" pages with actual memes.

Page 14354 has memes:
imgflip.com/?sort=latest&;page=14534

Page 14535 doesn't.
imgflip.com/?sort=latest&;page=14535

Still a lot, though, huh?

imgflip's first gif
imgflip.com/gif/536

I wonder why it was different numbers for you and me. Maybe our browsers fit a different number of memes on each screen to make the total number of pages different?

(I don't really know how that stuff works).

< -- FOUND AN EARLIER MEME (still Good Guy Greg!!!)

You got me curious to go looking at how far back the "Hot" page goes. Strangely it seems to go even further back (maybe the idea of a "Latest" page was added afterwards):

imgflip.com/?page=14571

^ as of 14/8/15