what should a 1985 speedmaster serial number start with?

[lps1994]

I am trying to find a speedmaster in my fiancés birth year. On many websites it says that omega serial #'s beginning with "48" are likely from 1985, however, it says specifically speedmasters have their own serial number system and that speedmasters from 1985 should start with "46" - is this true? I've seen many watch dealers say year of production is 1985 for their speedmaster but the serial starts with "48". So confused- any help is appreciated!

https://www.vintagemasters.eu/omega-serial-numbers-check-and-verify/

 

[Seaborg]

Again:
https://www.ilovemyspeedmaster.com/productiondateprediction/birthdate/

 

[Foo2rama]

For 1985, 46809949 to 47096509

 

[Davidt]

Bear in mind a Speedmaster made in 1985 would likely have been sold in 86-88.
If your partners parents had gone to a jewellers the week he was born and bought a Speedmaster, it would likely have been made a few years earlier.
So do you want a watch produced in 1985 or sold in 1985??

For this reason I wouldn’t get hung up on a specific year. Better to get one from broadly the right period (ie, early-mid 80’s) that’s in good condition.