As you apparently know chainrings are not quite universal. If you stay within brand, and check specs carefully you'll get best fit, maximum performance, and benefits like phasing for crisper shifting.
That said, the difference isn't earthshaking. Obviously you can't do anything about the anti-jam pin, but that isn't a crisis. As for the phasing, odds are you'll never get it perfect, but we managed to shift double and triple chainrings for decades without shift ramps, pins, shift gates and phasing. You can also rotate the inner and outer rings trial and error looking for the best phasing and get it pretty well dialed in. So it may not be perfect but after riding it a while you probably won't notice the difference.
BTW- I may tend to down play this issue, I still ride my old SunTour Superbe Pro cranks, and prize the ability to use any size chainrings I choose like 45/51 to optimize the gearing.
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FB
Chain-L site
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Last edited by FBinNY; 08-31-10 at 08:57 PM.