You have whats referred to as a Colt SAA (not SSA) aka Single Action Army. This gun is also called the model P (Colts catalog name at the time), the model of 1873 (the year of its introduction) and also, the "peacemaker".
Judging by the SN of 237XXX (I think, its hard t tell for sure. It could be 287XXX) it was made in 1902. This is a first generation SAA. First generation guns are pre WWII, and many were for black powder rounds but yours may be smokeless. These guns should be treated with care and respect. Your grips may be replaced, as they took too good when compared to the guns condition. The gun was most likely originally blued, some were factory nickel as well. Your caliber on the barrel is 38 WCF aka 38 Winchester Center Fire, which is also commonly called 38-40. The barrel length appears to be the artillery length, aka 5.5 in. To check the barrel length measure from the cylinder face out.
So whats the story behind this gun? Where did you find such a piece?