It is an Officer's Model, made in 1922. Have 2 Army Specials, (38 & 32-20) both shoot great. They have fixed sights, I think the Officer's Model indicate adjustible sights. Both models share the same serial number range. Fit and finish, inside and out not to be matched today. Great shooters.
This info per R.L. Wilson's Colt's Dates of Manufature.
"I walk on untrodden ground. Associate yourself with men of good quality if you esteem your own reputation. It is better be alone than in bad company." GEORGE WASHINGTON, (1732-1799)