Help with an ETA movement ID

[panerai153]

I recently purchased a genuine ETA 2893-2.4. the watch came sealed in the ETA pouch. The diagram clearly shows it to be a GMT movement, however I'm confounded by the extra .4 Does anyone here know what that means? does that refer to the date window position? Lastly, will this movement swap into my GMT Master IIC ? IF this fits with a minimum of difficulty, I would like to swap out the 1836 movement for this one. i know that it doesn't correct the hand stack problem, but it certainly increases the reliability factor, as this is a true GMT movement. IF that is possible, I would then like to swap out the crystal for a genuine, or get one of the AR coated under the cyclops ones.

Thanks

[RWG Technical]

My guess would be that this is referring to the height of the GMT/cannon/hour/seconds posts/gears.

If you remove the GMT gear and mic it, you will have your answer.