I know I get boring saying this, but do NOT carry any gun with a high value or of historical/sentimental interest. He should not be carrying a gun for fun or to show off. If he uses that gun, it will be seized by the police and he may never get it back (assuming he does not end up in prison). A carry gun should be reliable, but not a museum specimen or of other than ordinary value.
Jim
I agree. Fine old guns deserve to be retired and brought out once in a while for some fun informal shooting.
There are enough guns still in production, or recently ceased production that are modern versions of the historically significant models. A much better choice for carry, still historically significant, and does not carry the value of the fine, old firearm.
The M1911, Browning Hi-Power, S&W Chief Special, S&W Model 10, and the Walther PPK come to mind but there are others.