Hi, I have a 510.503 all original, but for some reason it has the wrong number on the back. It has 510.501 which is the black version. I have read that there have been some inconsistencies during the period in Heuer/Lemania's history...could this be part of that inconsistency? It has all the right markings and I have seen other in this color with no marking on the clasp.
I think it's more likely that at some stage in its life it was simply swapped for some reason. Both models have a stainless steel case back, and are identical apart from the reference number. Yes, there are plenty of inconsistencies over this period (position and placement of reference numbers, Heuer crown vs. no Heuer crown, etc), but in this case I'd say it was either a mix-up when the watch was first made or at a service since. Watch looks to be in nice original condition! Dc
Thanks D.C! I just thought it was a weird coincidence that a watch maker would've had a 501 and 503 at the same time and on top of that used the wrong case-back of the same series watch. And yes, this watch has a non branded crown which seems to be consistent in other 503's I have seen. Thanks again!