Why take a chance, just grease the rod, as the owners manual says to do if it is in not in use or in storage for a length of time. I'm getting a new clylinder after a tree fell on my BH and they cost $650 to replace.
The tree fell on the clyinder rod while it was in the extended position for a year - per owners manual - with grease, under a tarp, no rust or pits.
So, original poster, I think you have all our opinions and facts, your choice if you want to spend a few cents and a few minutes to grease your rod.
And make sure if a freak 70 MPH wind comes around no trees are nearby.
For those who said to store the BH with all rods in cylinders - that cannot be done without taking a chance of the BH falling and breaking hydraulic hoses during the removal. I guess you could take it off, build a supporting structure around it, reconnect it, and then retract the rods, but it's easier to grease the rods per owners manual.