I do not believe the 19-3 has a pinned front sight - I think it's not part of the barrel forging but braised on later, then the edges machined. I have a 66-1 2.5" (same engineering run as the 19-3) and a 2.5" 19-5 and neither show signs of being pinned. The larger N frames that came with sight options were the pinned ones (like a 27, 29, 25, etc.), I think.
If this is correct, you are going to have to grind off that front sight, cut a new groove to accept a new sight, then drill and pin it in place. After all that, a re-blue is going to be needed to make it look decent.
If yours is a non-insert type, then you have two easy options:
1) Simply put some orange or whatever color fingernail polish you want on the serrations. This is cheap and very effective.
2) If yours has an insert but you want a different color, the kits DavidE mentioned are pretty much DIY.