The factory sights that come on most pistols (especially little guns) are pretty difficult to see. They’re usually small and black and acquiring the front sight during the presentation can be difficult. You also might be vetting a new pistol purchase, and before dropping $70-$150 on a set of new sights you can cheaply get easier to see sights.
$6 gets you fluorescent hobby paint and tiny brushes at a hobby store. I also purchased some white Nail polish at the dollar store.
This can also be accomplished with florescent tape with clear coat nail polish on the edges to keep it from peeling.
Reapply as needed.