It could be OK.
Hi Kay,
It could well be OK.
I have a 1995 dealers catalogue which shows a model like you describe.
the model number ( on a bracelet ) is 2583.20.00
the model number ( on a strap ) is 2883.20.03
Doing a quick google on the 1st number brings up the following picture
I would have scanned the Omega catalogue picture for you, but to be honest, the quality is not very good.
I wouldn't worry that Omega don't currently have a ladies seamaster with a white dial in their collection. You bought your watch 6 or 7 years ago. The collection has changed in that time.
I checked a 2002 Dealers Catalogue that I have & there is not a single ladies Seamaster with a white dial shown. So the model was no longer available in 2002.
I hope this eases your mind a bit. But to repeat what SD_GR wrote. you don't say whether you bought your watch from an Authorized dealer or not, or whether you bought it new or second hand.
If you bought it new from a dealer or got a good 2nd hand deal, you should have the warranty card etc etc with the same 8 digit number on them as is on the back of your watch.
There ARE a lot of seamaster fakes out there, but not that many ladies fakes.
Enjoy your watch.
Steve