The specified range is for the ``guaranteed'' parameters; i.e. they say that it will works at up to 60°C and, something like, it will drift at most 2 minutes each years;
going over range can result in many different behaviour:
- It simply don't work or maybe even break (quite improbable);
- It will work but it's lifetime is reduced;
- It will work with degraded specification, like drift 3 minutes each year (just an example)
- It will work perfectly but it simply wasn't tested at high temperature to be sure of that.
Often manufacturer do a product lot and then 'bin' the parts on some tested characteristic: maybe something like 30% isn't even tested and put into the 'low grade' bin, the other part are tested and binned accordingly. Pricing is done on the product yield.
Other times maybe the core component is the same but packaged in a more sturdy way (you pay for the package in this case)