Is a lower CHT on one cylinder cause for concern?
A 60 degree difference in CHT is something worth investigating: It may not be a safety-related issue, but you want to know if it's "normal" for the engine or an indication of a problem.

In order from roughly "Most Benign" to "Worst Case", the CHT difference could be the result of:


A faulty CHT probe
Either the probe is not seated in the cylinder head well properly, or the probe/wiring is defective and causing an inaccurate reading.
Different CHT Probe Types
Spark plug gasket probes can read higher than "normal" cylinder head probes, so if gasket probes were used on cylinders 1, 3, and 4 and a standard bayonet probe used on #2 that would account for the difference.
(I can't see why this would be the case though: usually you have one gasket probe - on the cylinder where the manufacturer's CHT gauge was connected because it's using the normal bayonet probe hole - and bayonet probes in the rest, not the other way around.)
A mixture imbalance
Cylinder #2 is running richer or leaner than the other cylinders. 
Since you say the engine is not running rough Cylinder #2 would probably be running rich.  (This is normally something you'd notice with Exhaust Gas Temperature rather than Cylinder Head Temperature.)
You can check for this by watching the engine monitor as you lean the engine: Cylinder #2's EGT will peak at a different time than the rest of the cylinders (early = leaner, late = richer). On fuel-injected engines this can be adjusted for by using tuned injector nozzles. On carbureted engines you just have to live with it - but at least you'll know the cause and be able to determine what "normal" is for this engine.
Fouled/Failed Spark Plug
Easy to check in-flight: Cycle each magneto; If the cylinder dies on one you've found the culprit.
(Something you should probably catch on your preflight mag check too.)
A cooling problem
If the cooling baffles for your engine are worn/damaged/incorrectly positioned you might have anomalous airflow that's directing more cooling air over the #2 cylinder head than the rest of the cylinders.
(Normally you find baffle problems because one or more cylinders are running hot, but cold is possible too.)
A cylinder problem
An exhaust valve that's not fully closing can cause low CHTs - your mechanic can confirm this with a borescope (or a compression test -- they'll hear air escaping through the exhaust if the valve isn't closing).
If this is the case it's something to attend to, because if it's ignored it can lead to an exhaust valve failure, which can ruin your day.