I believe the issue is not so simple as that 1163 bezels are angled, and the 11630 bezels are flat.
It is true that the 1163 bezel insert is angled upward from the outer bezel to the inner edge.

However, I think that, as always with Heuer, it is not so simple. There seem to be two slightly different styles of 11630 bezels. There are the completely flat bezels inserts, and there are bezel inserts that are angled upwards, much less so than the 1163, but still perceptibly angled.

Look at these photos I took of some NOS bezels I have. These bezels are from Heuer watchmakers and are real Heuer parts, I have no doubt about that. I compared three bezels, a diver 11630P bezel (never issued for the 1163) on the left, a tachy 11630T in the middle, and a classic 1163T Tachy on the right.

Certainly you can see the 1163 is much more angled than the others. But look at the 11630T compared to the 11630P. The P bezel (left) is almost completely flat, but the outer edge sits proud of the metal bezel surround. On the 11630T bezel, the outer edge fits right into the metal bezel, completely flush, then there is a small angle up to the glass.

I am 100% sure these are real Heuer parts, the only other possibility is that the middle bezel was intended for an 1163, but I think any bezel insert with a lume dot on the triangle, is for an 11630, so I am pretty sure this is an 11630 bezel.

Please go out and check your 11630s - are the bezel inserts always really really flat? Does the bezel insert outer edge fit flush or sit above the metal bezel holder?

Any views?