That should be a .45 Hand Ejector Model 1917. Caliber is .45 ACP using moon clips, or .45 Auto Rim.
These were made for the US Army up to serial number 169959 in 1919. Guns were sold commercially in the inter war years, but sales were slow. Serial number 180455 shipped in 1929.
Yours falls outside the main serial range for guns made for Brazil and shipped in 1938, but may have been a Brazilian contract gun anyway as serial numbers as early as 169xxx shipped with that contract.
It should be marked S&W D.A. .45 on the left side of the barrel and made in the U.S.A. on the right side of the frame. 1909 patent dates on the top strap.
There will be a Brazilian crest and the date 1937 on the side plate if a Brazilian gun.
If there is 4 line address instead of Made in U.S.A on the right side of the frame, then it is a post WWII gun put together by S&W using surplus parts.
A commercial sale gun will have higher collector value than an Brazilian gun as there were 25,000 made for Brazil, with the majority re-imported as surplus in 1990.
Value of a 4 line address gun will be hard to tell. There were 10,000 made.
I highly recommend you take some pics and post them in a new thread for appraisal. Collector value is highly dependent on condition. A fair condition gun may go for $400, a mint condition gun up to $3000.