Sorry to disappoint, but there was no "all Pencil Puzzles" issue. We stopped doing the puzzles around 2005 because we no longer had that newsprint section in the middle of the magazine, and the puzzles didn't work on the glossy pages.
We did bring the puzzles back in the Tips & Tricks Codebook after the monthly Tips & Tricks was discontinued in 2007, because the Codebook was almost entirely newsprint. After that, they appeared in every subsequent issue until the last one came out in 2011. Come to think of it, there may have been one issue with more puzzles than usual - like eight or ten of them instead of the usual two or four, I can't remember exactly. Maybe that's what you're thinking of.