A 1939 is not a rare example unless it is marked differently than normal. But if it is a non-import with original finish it will bring at least $250 and likely more. I will pay up to about $400 for any prewar all matched revolver at a show if I don't already have an example or it has an SA mark (I always pick up SA marked revolvers as it is easy to find them new homes with guys who collect Finnish rifles - I have one right now looking for a new home).
The holster is another matter. Without pictures I won't hazard a guess. If it is a recent import, post war made for storage it is worth $15. If it is an original M1901 or M1910 it is worth hundreds. If it is a 1930s or 1940s original it is worth between $50 and $100 depending on model and condition.
"Never increase, beyond what is necessary, the number of entities required to explain anything." William of Ockham (1285-1349)