Meprolight sights cannot have the lamps replaced due to the adhesion process. Tru-Dot sights are warranted for 12-years. You are welcome to send them in for inspection and if they cannot be replaced under warranty, we may be able to offer you a customer loyalty discount.
That sucks I just bought some for a 5900 3900 4000 series pistol for $2 at a local gun store in their bargain box. The sights still shine a bit but no where near what new ones should be.
I bought Mepro Lights for my 3913TSW. I had them installed and then found out that they tend to shoot low on 3rd Gens. They only make one height front sight, so that's no an option.
At some point, I'll get something else and have those installed. Kind of a bummer, but that's how it goes sometimes.