Correct or "Service" Great White case back?

[Filipão]

Hello Experts,

My great Great White has a case back that's been troubling me.

It's a MK4 very low 8 million from 1983 as in pictures.

Is this a service case back?

Thank you!

[Filipão]

Hello dear Experts,

I have researched a bit and concluded that late production 1665 GW came with these type of casebacks. Mine is a 8.050 million.

A very similar type of case back was thereafter sold as "Service" case backs, fitting all 1665s.

But a closer look to the "Service" case backs, reveals them to be quite different.

The regular production ones have fatter coronets and all verbiage is engraved farther inside the case back circumference, on a tighter radius that is.

On the left is a regular case back, right side a service one.

The other 2 pictures depict the service back too. Take a good look at how long and slim the service coronets are.