At this point there is no need to get K frame grips, Get a sharp pencil and draw around the frame where the grips hang over. Then use a wood rasp or course sand paper to take the grips down to the pencil line rounding then a bit, then go to finer paper. Some oil finish and your done. If you want fill the grooves with some kind of filler like Epoxy with coloring, JB weld, or get some saw dust fill grooves with super glue and saw dust and repeat until filled lightly sanding between coats.

Use brass wool and Kroil to clean up the rust, Fine files and sand paper backed by something like a small piece of flat bar and round stock to clean up the rough spots. Get another ejector rod with the knurling on it and install. Tear it down and clean the guts up, stone any rough spots except the sears. Find a drill that fits the hole for barrel pin and install, if the barrel itself is not drilled, drill it out going easy so you don"t snap the drill. If you take your time and think of it as a project you can make it look pretty good. Once it is all looking good you have home finish options, Disassemble, put exterior parts on a cookie sheet and put it in the oven at say 300f. Then use a Q tip and cold blue to touch it up. Or first remove all the finish with naval jelly then use some Plum Brown and the heat to make it a dark purple. Or once it is stripped to bare steel and cleaned up, take a small box and stick it in the box with a rag damped with salty water. Either stick it in a warm place or if the box is big enough place a light bulb in it. Every few days remove it and wipe off the rust with fine steel wool. Repeat a bunch of times and then stick it in a pot of boiling water for 30 min or so, then oil it well for a decent rust blue. Shoot the snot out of it.

I wouldn't worry about the soot on the brass much. 32 S&W is pretty low pressure and the brass probably isn't blowing out very tight in the chambers and letting some burning gas come back a bit.