P8riot, you did not tell us why you want the target trigger and hammer, so I am not sure if you are looking for opinions on these parts, but I will offer my thoughts.
I don't like a target trigger or a target hammer on a gun I intend to shoot. I certainly respect that many collectors prefer these parts, and some people do prefer them to shoot with, but for me there are disadvantages. I really don't like a wide trigger for shooting double action. I don't like it much for single action either, but for double action it really does not fit my finger. I don't think I have ever heard someone who prefers a wide trigger for double action shooting, though I am sure there are some people like it.
I am more ambivalent about the target hammer, but I still don't need one. I don't have any trouble cocking a standard hammer for single action, and in double action the heavier target hammer can require slightly more mainspring strength than a lighter hammer.
Overall, I feel that the target parts are designed for single action shooting, but are not that well suited for double action. Since I do a substantial amount of double action, I want parts that work well for either style of shooting.
I also recognize that since many people think that the target trigger and hammer are desirable, the parts have good value. The matched set of hammer and trigger that you described are worth a fair bit in the current market, so if I was installing them, I would want to be sure that it was done properly.
Since you said that the parts are a matched pair from a similar gun, I think that it is reasonable to try installing them and see if they work properly. This is assuming that you are well familiar with doing a full disassembly on a S&W revolver. However, if the parts don't just work right away, then I would recommend having a gunsmith complete the installation. Once stoning parts is required, there is always the risk of making things worse if you don't know exactly where to cut.
