For a time, I had the model with adj. sights and a barrel about 5.25-inch.
From my recollection of the frame size, I'd try holsters marked for S&W K-frames. I wore mine on a duty belt in a Safariland Model 29 holster bought originally for a six-inch S&W M-19, also worn with a Ruger Security-Six.
Colt .41 frames are larger. Holsters for L-frames and GP Rugers are also too large. You will have a hard time finding Colt holsters for three-inch barrels, anyway. Pretty hard, even for S&W's.
I'd call El Paso Saddlery and ask if they'd make a holster. Look at their line first. I think what you may want for open carry is their version of the Safariland M-29. Model 2. I have a couple, one for a S&W M-60-4. Nice work. I think I have four EPS holsters and one belt. All are beautifully made. I caution you, they often have a long delivery time, due to heavy orders and lot of talented hand work involved.
For a concealment rig, I might look to Lobo Leather. I don't know their model numbers, but have seen some here that look really nice. A friend on this board has one for his S&W M-66 snub, and he really likes it.
Overall, I THINK you can find joy in holsters made for S&W K-frames. But they may vary a little. And few used ones will be for three-inch barrels.