I have a question, I was given a model 66-4 4" for my 20 years of service with Smith & Wesson back in late 1999. I had removed the sight assembly to mount rails and scope. I have lost the assembly. I'm looking for a replacement but what sight blade measurement should it have had? .196, .146 and it had a white outline as well. I'm looking to hand engrave it and leave it to one of my boys and want it close to original

.146 blade height.