Hacking seconds on ref 1803?

[FrmrHoss]

I'll try this amongst the vintage experts since I've had little luck searching and in the "reference" forum - I've read in a few spots that Rolex added the hacking seconds feature to the 1803 Day-Dates in the early/mid 70s. Can anyone with more knowledge than me on this topic confirm?

To get more specifically to the point, the 1803 I recently acquired definitely has the hacking seconds and the serial no. puts its production probably around 74/75, so it follows with the little bit I was able to find out about it on the web but trust some of the knowledgeable folks here moreso than random websites. Thanks!