This reminds me of a rather remarkable coincidence that I noticed several years ago in The CHUM Chart Book (which I know you have). It shows that in 1967, "The River Is Wide" by The Forum peaked at #14 and spent 6 weeks on the chart -- and then in 1969, the same thing happened with The Grass Roots' version. However, it should be noted that the CHUM Chart consisted of 50 positions in 1967, but had been shortened to 30 positions by 1969. So there's a good chance that The Grass Roots' version would have been on the chart a bit longer if it had still contained 50 listings.

Yes, it's the sort of thing that a skeptical person could think had been done deliberately -- but I think it was just a complete coincidence. My guess is that The Grass Roots would have had a bigger hit with the song here if The Forum's version hadn't done as well as it did; I like both versions but prefer The Forum's, and I think that most people who bought it wouldn't have then wanted to get the same song by The Grass Roots less than two years later.