If the serial number is in the 20,000 range as it appears to be, it is a pre WW II .38 Super. (The last Super before Colt went over to wartime production of .45s was near 37,000.) The .22 conversion has the old style adjustable sight and is very likely prewar, also. In its factory box, too. The outfit in UNALTERED condition is worth a good deal of money, two or three grand in the Blue Book. I'll look at some ads and see what the speculators are asking for them.
Unaltered. Don't be tempted to have a nice old piece like this refinished or customized. If you don't like the way it shoots buy something new. Any alteration could cut its dollar value in half.
Not to mention the family connection which would be worth a lot to me.