.32-20 Hand Ejector Model of 1905 4th Change manufactured between 1919/20 & 1940 in the serial number range 81287 to 144684. Based on the pre-WWI manufacture rate of around 4000 guns a year I would guesstimate your gun as being from the mid to late 1920s.
For an exact shipping date you would need to pay $50 to S&W to have Roy Jinks the factory historian look up the original records and send you a factory letter listing his findings.
56853 would be an assembly number used to track parts in the factory, it has no meaning after the gun is completed.
Don't use any old Hi-Speed jacketed ammo in this gun, the jackets had a habit of stripping off in the barrel and then the next round fired into the jacket would cause a bulged barrel.
Your gun was manufactured after the introduction of heat treated cylinders so it should be safe to shoot with current factory lead projectile loads.
It lacks the positive internal hammer block safety introduced in 1944, if dropped it could fire. It would be prudent to leave the chamber under the hammer empty.
I've no info on the holster.
