Re: age on an Iver Johnson .38
Welcome to TFF.
Is the serial on grip frame on bottom end of butt or left side under the grips?
If the serial is on bottom end of butt, the frame was made in 1895, and it's an antique 2nd model, per U.S. federal rule.
(It can't be an 1894 first model or the later barrel assembly would not fit)
The barrel address with no patent dates and an asterisk or star at ends was used 1914-1941.