I am new to this forum, though I have been corresponding with Chuck Maddox over the last couple of days via email. I have a Heuer chronograph that I purchased new back in the mid-80s; it is stamped "510 501" on the back. When I look at the 1985 catalog posted on this site, however, I see an anomaly. My watch has both day and date; according to the catalog, this should be a 510.502.

I have never had the watch worked on until last week, and the back was not changed, as I have pictures of the watch I took just prior to sending it to the watch repairman.

Can anyone shed light on this?

Thanks,
Walt