I agree, what do you really gain by using a hotter load? Are you going bear hunting? For self defense or shooting at the range a regular 38 special round will suffice.
Here some directly related thread on calguns:
+P ammon in S&W Model 49 revolver - Calguns.net
If you are set on wanting to shoot +p just sell your old one and get a newer model that is factory approved for it. The 80s model should sell for good money.
George