Is this F1 series 3 case authentic?

[gkmaia]

I bought this case on ebay. And as it arrived I could note a few traits and not sure it is authentic. 

The dial and case back are authentic. But the case itself... i've never seen a case like that before. 

The seller is adamant it is original. 

Could you give your opinion?

[rodabod]

Have you checked if there were any design revisions over the years?

[HSL]

2 hours ago, rodabod said:

Have you checked if there were any design revisions over the years?

I was thinking the same, without seeing the whole back it is hard to see what is going on but what if feels like is I’m looking at one newer version like the from 2018 or something while the left “Replica” is the original one housing an ETA G10.711, therefor the slightly thicker back.
The "rubber bumpers" on these ones are of a notoriously bad quality so it isn’t impossible what we see here is just the rubber worn/split away, hence the different shape in the corners by the rubber.
At https://www.calibre11.com/overview-tag-heuer-formula-1/ one can see the difference in the original dial of the Series 3 with the text 200 M instead of the later version using 200 METERS. (The right one has the exact same layout).