Dear Mr. Miarecki,
Please don't take this personally. I'm not certain what you meant by "Have a great time on your forum", and whether it was directed to me, someone else, or all of us posting in this topic. To be fair, either this forum belongs to Ryan, or it "belongs" to all of us (yourself included), which would make it "our" forum - perhaps a bit of both. In any case, with all due respect, I don't understand why we can't disagree about some minor detail of a relatively inconsequential prop and still be civil about it.
Considering the poor resolution and quality of the available references, I'm still not convinced of your position. But I'm not 100% certain of my most recent one either, and I don't believe the references provided here thus far are sufficient to prove or disprove either of them (nor any of the previously proposed theories, for that matter).
Below is a marked-up detail version of the image in question, illustrating what I believe is the profile of the far side of the inner circumference of the lens bezel. I have overlaid two identically-shaped ellipses; the green one roughly coincides with the upper edge of the bezel, and the yellow one, which I have trimmed where it intersects the green one, represents the lower edge of the bezel, presumably in contact with the upper surface of the lens. Note that above the approximate center of the lens and between the upper green line and the yellow line, there is a medium-gray-toned region bounded on its left and right sides by approximately vertical specular highlights, which are presumably reflections of studio lights coming from the micro-grooves in the machined surface of the metal bezel. Allowing for optical bloom from the bright areas on the bezel and lens, this gray region does not appear to be deformed or obstructed from the size or shape one would expect to see if the upper surface of the lens were flat.
Thus it seems to me that, if the center of the lens' upper surface is raised at all above the flat plane defined by its outer circumference, it must be by such a minuscule amount that it does not obscure the lower edge of the bezel at all, even at this shallow viewing angle. So if the lens is indeed conical, I'm forced to believe that it must be either an extremely shallow cone, or an inverted cone, flat on the front surface but pointed on the interior of the prop. In either case, in my opinion the photo doesn't provide sufficient evidence to prove or disprove it. I'm sure several of us here could replicate this prop with either a flat lens or a shallowly-conical, upward-pointing lens and take a photograph of it which closely resembles this photo.