I was wondering about my 48-4, 75K6781, and this older MP 38 Spl, two inch, square butt: 80188
75K6781 = 1980.
80188 = Assuming it's a 6 shot, SN's ran from 73251 in 1906 to 146899 in 1909. But, they were not offered with a 2" barrel.
There would be a matching serial number on the rear underside of the barrel if it's original to the gun.