I agree with handejector. I have 2 17's from 1948. The early one has a single address line, the other a 4 address line. Both have a matte finish. It is my understanding, mostly from this forum, that the matte finish was standard in this era, but a glossy finish was available via special order. It is entirely possible that a distributor ordered a quantity of them in glossy finish. The one thing you can be assured of with S&W is that almost anything is possible, no matter how improbable!
Post some pictures of that fine gun and let us help you determine the truth. Please post pictures including both sides of the grip frame without the grip.