That does look like a fix, but I can't see spending $60 to replace a $0.0001 bit of plastic.

The rest of the supplies would dry up before I could find a use. I guess my Plan B is to attempt to rehab the original sight with some sort of med/fine abrasive. If I mess it up, I'll yank it out and go cut up a bright orange slide stop/chamber flag (or whatever it is...see pic) that came with one of my S&W autos and epoxy it in place - of make a "dam" / form and melt it in place.
I'll post results of the debacle upon completion...
Regards.