The hole in the spindle ends is where the grease nipple would go if it was a greasable spindle
Yours appear not to be
IF the hole has a thread then you can try to screw a grease nipple in there but in new machines the spindle nipple is generally a press fit ( where fitted )
California models will not have grease nipples
As you seem to want to look aster your mower properly then get a can of white lithium spray grease .
Make sure the can has a straw
Apply it liberally where ever 2 metal bits move between each other deck lifts , lap bars & tension pulley arms