yup, having a look inside certainly won't hurt.
nevertheless, I think any good quality relais should do, the pin assignment should be easily determined by looking at the surrounding circuitry.
As for the coil resistantce: actually if the new ones are higher (I read that backwards) there definetly should not be an overload on the driving circuitry as the current goes down with higher resitance.
(unless my brain is in SUnday mode right now and I'm talking rubbish haha)