Bad Battery or is this normal reading?

[VQLT]

on 5/28 I reconnected the battery and measured voltage. prior to connecting it read 12.34 once reconnected the immediate reading was 12.18.
The following day 5/30 the reading was 12.15

 

[bonjo]

those volt readings are not good for a disconnected battery. For a lead acid battery, I would expect the volts tp go down from 13 but not below 12.5 even after a long period. AGM 12.8
The battery may have lost some capacity even before you bought it.
You can use a smart charger (CTEK) with desulfation & maintenance mode to try to recover some capacity loss.
I use CTEK with very good result on older batteries. Also have the small nogo genius 1 which I find totally rubbish.