has anyone come across this before 'Rolex double model number'

[dennyboy]

has anyone come across this before and i so could you please shed some light on it for me.
you can see 6494 lined out and then 6422 engraved underneath.

when i got this i was told it was a rare precision non-date early 1957.
i was told they used up some of the older slim cases before moving on to the newer cases and these are very rare to find.
once again this is just what i was told when i got the watch, i really have no idea

[Tools]

It's pretty common for the era.

[Dr.Smellody]

Very common. These used whatever was available at the time of assembly.

[joe100]

yep, just saving parts. as one rolex exec put it, and i'm paraphrasing: "our customers should never see the inside of their watch"

[watchcrank]

Common as the brand worked through parts.

[dpa94114]

i thought it was totally bizarre the first time i saw it...but was informed of the authenticity

never really thought Rolex was worried about extra parts

[J!m]

You see a lot of 5513 backs on 5512's too. Pretty normal.

[rolfiz]

If only it was on the dial, then it'd be worth thousands! ;)

[harry in montreal]

I saw some tudor subs with the serial number printed on the inside of the case back.

[J!m]

Originally Posted by harry in montreal

I saw some tudor subs with the serial number printed on the inside of the case back.

I think those were the military issued variant...

[dennyboy]

nice one thanks for the advice, i was a little worried at first but i only gave £650 for it, i think that works out about $1000

heres a pic of the front

[dennyboy]