[targa911S]

don't bother calling Colt. They are a bunch of A holes and will want $200 for a letter on that gun. You can go to proof house.com and put in the numbers and get the year of manufacture. from that site I find it was made in 1952 and is a combat commander vs the commander 9mm commercial. You will like shooting a 9mm. I may be wrong but the slide may have been chrome plated at some time..
Colt did not do chrome. They did nickel, but the whole gun would have been done. Tabs can weigh in with more as he is a Colt guy.