I have NVRam in a few of the pins. The couple that doesn't have the NVRAM and I installed Lith batteries.
Just about a year ago I had some spare alkaline batteries set aside for flashlights. New, good name brand that had a shelf date ages from now. Leaked in the sealed package. Whatever you do, don't install alkaline.
On a side note, I have a desoldering gun - sure makes pulling a chip out a lot easier.
Didn't someone make a RTC for pins?