Timing Chain & Rough Idle...Cause and Effect?

Forum, Sanity check please.....after having head work done, I suspect the mechanic replaced the timimg chain 1-2 links off the cam sprockets which has resulted in a rough idle. Does this make sense as to cause? I've eliminated everything else (I think). How do I test/check this? Valve clearance at TDC? Which cylinder valve? What should measurement be. TIA for your help!

[Benzmac]

1 tooth and it will run, 2 and it will bend valves. I would have the base heights checked on the valves!!! There is a special tool for this.

Thanks BenzMac...The car runs and runs smooth except at idle. Based on your reply, the chain may be correctly installed after all.