Nick: You can look at this weeks post of "Front End Friday" from 8/5/21 to see my 152. The 152 was made between 1917 and 1927. One of the easiest ways to quickly date more closely is to look at the headlight. There are pedestal (early) and "strap"(1919-27) variations as to how the headlight is mounted and my strap headlight plus some other features dates the engine from about1923. You can also look at Greenbergs very detailed text, "Greenbergs Guide to Lionel Trains, O gauge, Volume 1, 1915-1928" . On page 80, the book contains a dating table devoted to the 152 which should help to better date your engine. I would repeat the comment others have made, these early engines used parts from various years if they happened to be in left over inventory so look for several "markers" to date your engine.
Don
