Originally Posted by murphydog

Good information above; a model stamped steel K frame in .38 Special such as your 10-2 has been approved for factory +P for many years. Quotes from factory sources suggest metallurgic changes as the reason for this.

But this was not approved for steel (or alloy) J frames with model numbers - not pertinent to the question at hand but still true. Approval for these didn't occur until the late 1980s to early 1990s.