I personally think the theory of the rifle losing power after being cocked for extended periods is less likely to apply to the majority of modern airguns with decent quality springs fitted.

Perhaps at one time it might have been the case if the quality of the spring was suspect.

For instance I recently resprung my HW80, it was running a little quicker than I would like, so I cocked it and left it locked in the cabinet (with a note attached to remind me it was cocked) for a week - guess what no reduction in velocity, so it is due to have a coil lopped off, close and regrind the spring end to achieve what I am looking for.

I really don't think you have anything to worry about with your HW97K. In fact I would find it exceedingly difficult to hunt without carrying the rifle loaded and ready to use..