Fischer-Spassky Game #17 -- Threefold Repetition?

[HumbleProgrammer]

I was looking for some "threefold repetition" games to test a homebrew PGN tool, and remembered that the 1972 Fischer-Spassky match included several such draws. Sure enough, Game #17 is annotated as a threefold repetition draw on Wikipedia (and several other sites) but my tool failed to find it. Looking at the game, I don't see a threefold repetition either. Am I missing something here, or is Wikipedia misinformed?

[Event "Reykjavik-Wch"]
[Site "Reykjavik-Wch"]
[Date "1972.01.18"]
[EventDate "?"]
[Round "17"]
[Result "1/2-1/2"]
[White "Boris Spassky"]
[Black "Robert James Fischer"]
[ECO "B09"]
[PlyCount "89"]

1. e4 d6 2. d4 g6 3. Nc3 Nf6 4. f4 Bg7 5. Nf3 c5 6. dxc5 Qa5
7. Bd3 Qxc5 8. Qe2 O-O 9. Be3 Qa5 10. O-O Bg4 11. Rad1 Nc6
12. Bc4 Nh5 13. Bb3 Bxc3 14. bxc3 Qxc3 15. f5 Nf6 16. h3 Bxf3
17. Qxf3 Na5 18. Rd3 Qc7 19. Bh6 Nxb3 20. cxb3 Qc5+ 21. Kh1
Qe5 22. Bxf8 Rxf8 23. Re3 Rc8 24. fxg6 hxg6 25. Qf4 Qxf4
26. Rxf4 Nd7 27. Rf2 Ne5 28. Kh2 Rc1 29. Ree2 Nc6 30. Rc2 Re1
31. Rfe2 Ra1 32. Kg3 Kg7 33. Rcd2 Rf1 34. Rf2 Re1 35. Rfe2 Rf1
36. Re3 a6 37. Rc3 Re1 38. Rc4 Rf1 39. Rdc2 Ra1 40. Rf2 Re1
41. Rfc2 g5 42. Rc1 Re2 43. R1c2 Re1 44. Rc1 Re2 45. R1c2
1/2-1/2

Cheers!
Humble Programmer
,,,^..^,,,

[BB+]

This is just FIDE rules. You have to claim the draw before making the move that will produce a 3-rep. So Fischer claimed that Re1 would give a 3-rep (after moves 41, 43, 45). But the move is not made on the board. I have no idea how anyone came up with this rule, or its rationale, but it's what it is.