All Mercedes AMG wheels are 5 x 112, the real question is what model car they were manufactured for.
The back of the wheels has all the answers, as both the sizes and part numbers are cast into the wheels.
They are obviously Monoblock I's , but the shape of them makes them appear to be S class wheels. SL's also had Mono I 18" wheels as an option but I think the spokes are a little more tapered.
If they are S class wheels, expect high offsets.
Anyway, the seller need to post the 3 sizes he finds on the back side of these wheels.
Will look like this example
front wheels may be = "8.5J x 18H2 et44"
rear wheels may be = "9J x 18H2 et44"
They look like W220 wheels...