I really like to dive down and prove gauges, etc, are reading correctly, and dive down into the spec to make sure everything being monitored is in the normal and expected range.
But, even before I know the true spec or have proven the instrumentation -- I find it worth an immediate investigation if anythings of any importance show differently than they always has.
So, even while you are hunting for the spec, if you aren't already, I'd just keep an eye out for changes and also check the accuracy of the gauges whenever you have the chance.