The T1 Mark is in the correct position - maybe a tiny bit to the right of the pointer. Hard to be certain from the photo.
It is almost impossible to get an accurate line of sight in order to assess the position of the L-Ex mark in relation to the surface of the casting, and it is very easy to convince yourself that you have them out of alignment.
Again (from the photos) I would suggest that your L-Ex mark is also spot on. In spite of the fact that it looks a tad too high.
Here's why I think that. It looks to be a tad too high, because the camera is looking down onto the top of the casting. How do I know ? 2 reasons:
1) You can see the joining surface. If you were looking absolutely horizontally, then non of the top surface of the of that front crankcase cover would be visible. Your line of sight is a tad too high, which means you can see a gap between the top of the crankcase cover and the index mark.
2) The shadow is parallel to the top surface of the crankcase cover, and the index mark is parallel to that. If the timing was one tooth out, there would be a small but noticeable angle between the LEX index mark and the shadow.
But you need to convince yourself. Get a mirror. Find a light source that will cast a good clean shadow (LED lamps are not very good at this, I find). View the top of the crankcase and the L-Ex index mark through the mirror. Raise the mirror too high so that the index mark seems to be higher than the surface of the crankcase cover, and then slowly lower the mirror. Watch the top surface of the front of the crankcase cover - not the index mark. As soon as it disappears from view, you are looking from exactly the right point. The L-Ex index line should be immediately in line with the front edge.
Then use your flashlight - to convince yourself again. Instead of the mirror, point the flashlight from the same place, and watch the shadow. The shadow should sit exactly on top of the L-Ex index mark at one point - the mark should not be at an angle to the shadow. I can see this is the case from your photo.
Note that the shadow from the camera flash is a bit misleading, as the lens is not in line with the flash - the photo indicates that the lens is above the desired line of sight, the flash is below. However - it does show that the L-Ex is parallel to that front surface.
Finally, rotate the engine 360 degrees (anticlockwise) so that T1 is again aligned with the pointer in the windows. Now L-Ex and L-In will be facing each other. Both of them will be in line with the top of the crankcase cover and in line with each other. If one of them is even slightly at an angle it will be very obvious.
The lobes do look a little different - but the camera position isn't helping - it is able to see more of the cam for the intake than it is for the exhaust - as are you.
To answer your other question - Is it possible to mess up the timing by playing with the cam chain tensioner ?
Theoretically possible, but in my opinion, unlikely if there is no movement in the cams or the engine. The risk would be that the chain loops under the smaller lower sprocket at the end of the crankshaft (half the size of the cam sprockets). But how would the chain disconnect with all of the teeth down there without any movement ? (Not a definitive answer - just my thoughts).
The real danger of this happening is when shims are replaced - you hear of people marking the chain and the sprocket so that they are put back in the same position when the camshaft is re-installed - ignoring the fact that with the camshaft removed, the chain could have become detached from the sprocket at the lower end and is now a tooth out from where it was before.
But if your T1 is lined up, and your L-Ex and L-In are aligned as described in the manual - you have that eventuality covered.
