That be a 3.5 x whatever model / instead of the 4x model. The eye relief is a little longer on the 3.5 and the FOV is a tad wider too IIRC.
See if you can google the numbers on the optic to get confirmation if it is a 7.62 retical or a 5.56. Lots of folks like the 7.62 b/c 77 grn flys closer to the indexed stadia. Google and learn the dimensions of the stadia such that you can fractionalize it (ex my 4x 5.56 based doughnut of doom - the horizontal stadia are 19” at the indicated distance.
Is the lamp still good?
ACOGS while limited, are durable, have excellent glass, are caveman simple and very fast up close if you can get your head around the concept of keeping both eyes open, but use your non optic eye to feed your brain in order to acquire and swing on to POA; as the muzzle arrives on POA, the visual input stimulus to the brain switches to the optic eye, shot is made, visual stimulus now shifts back the non optic eye and searching repeats.