hello ,,heres the best site i know for dating a colt pistol
http://proofhouse.com/colt/index.html it should be able to give you the year of production for your aunts pistols,,the second set of numbers on the release are proably the assembly numbers and you may find them on the yoke and possibly on the face of the cylinder mabey under the ejector ,,sounds like a 41 new army or navy model.. possibly a 1889 model or a 1892 model,,once you figure out which it is i can better give you a value,,if you still can't figure which one you have ,,give me the patent dates and i'll cross refrence them for ya
bigcurt