I am not aware of any manufactured by Smith & Wesson, but I believe that Uncle Mike's made a K/L Frame boot. UM supplied the J Frame boot to the factory for awhile. Also, Byron's / Vintage Industries are a good choice.

It's funny. I spent years removing the stock rubber boots. Now, I appreciate them as highly functional. Buying the old school Uncle Mike's at every opportunity.

Here are Byron’s on a 19 2.5”