The Earth Sun L point-1 is about 1 1/2 million km away from the Earth and towards the Sun.

The Earth Moon L point-1 about 300,000 km away from the Earth and towards the Moon.

From the prospective of the lunar surface:

Earth/Sun L-1 varies in distance and is always roughly in the direction of the Sun, but it's apparent position varies depending upon where you are on the surface of the Moon.
The Earth/Sun L-1 will appear to be in the middle of the sun or to left or right of the Sun, depending upon the Moon orbit and your location on the Lunar surface.

At the Moon's poles in a location where you could see the Sun constantly, when the Moon is nearest to the Sun AND furthest from the Sun in the lunar orbit, the Earth/Sun L-1 would be directly aligned to the middle of the Sun.

At the Lunar poles on lunar surface, marking the start of the "day" when the Moon is closest to the Sun:

The "day" starts with Earth/Sun L-1 appearing to be exactly in the middle of the sun. In the first quarter of the day [about 7 days/1 week] the Earth/Sun L-1 would start by "leaping" away from the middle of the Sun, and after a few days, it would slow down. At the end of 7 days, the Earth/Sun L-1 would appear furthest from the Sun.
In the second quarter, the Earth/Sun L-1 would appear creep back towards the sun, but accelerate as one got near to the end of the second quarter.
In the second half of the Lunar day it repeat the same pattern, but switches to the opposite side of the Sun.
On the north pole, "the day" starts by Earth/Sun L-1 appearing to go right of the Sun and the second half of the day with Earth/Sun L-1 appearing to go to the left of the Sun. On the South pole the day starts by going in the reverse direction.

And at it's furthest, from the Moon the Sun Earth/Sun L-1 will appear about 15 degrees to the left or right of the Sun.

Now, from Earth both L-1 appear stay in the same location relative to the sun or Moon.

Though if there was say 100 km square solar panels, antenna, or some kind of reflector at Earth/Moon L-1, it's shadow on the Moon would shift around. And suppose that it's apparent location would also shift somewhat.

What would Earthling see, if there was 100 km square solar panel on the Moon surface on the near side, and one in each of the two L-1's?

Of course, during the day, you wouldn't see anything. Or would you? You can see the moon sometime during the day.
Now during the nite if it reflected sunlight towards you it could appear as a bright star, in any of these locations, though Earth/Sun L-1 on Earth is always in the same location in the middle of the sun and couldn't see it at nite.

The Moon's diameter is 3476 kilometers, and a 100 km square would be about 1/35th of this size. So, unless it's reflecting sunlight directly at you you aren't going to be able to see at all without a telescope or binoculars.
The 100 km square at Earth/Sun L-1 will be 4 to 5 times further away than the Moon. How big would it appear as a "sunspot" on the Sun?

If you had a picture of the Moon taken from earth which made the Moon appear 3 1/2 inches across, the 100 km square would appear as 1/10th square on the Moon, so the 100 km sq at Earth/Sun L-1 would appear on 14" picture of the sun as about the same size.