The 7" barrel takes rear sight blade 06558 and that isn't listed for any of the revolvers. Revolver rear sight part numbers start with 04xxxx, 05xxxx or 22xxxx, nothing starting with 06xxxx. The 06558 is the only blade listed for the 7" Model 41 and my S&W parts catalog shows it at .213" in height and $9.49 in price.

Stu