Is it in that exact configuration, or do you mean it has an A2 style fixed carry handle? Because that picture shows an A4 style removable carry handle which you could just take off with thumbscrews, and then mount an optic of your choosing on the rail. The front sight doesn't need to be removed to be used with many magnified optics- I have a carbine with both a front sight post and a 1-6x LVPO, and the post completely disappears as you zoom above 2x.
If it is an A2, DO NOT have it chopped just to kludge some rail onto it like it's 1984. People are paying crazy money for just an A2 upper receiver with rear sights right now because there's a resurgence in the popularity of retro builds. Here's a Colt A2 upper selling for $305 with 6 bids and a day left on the clock:
You can get a carry handle mounted optic like others have said, or if you want to really modernize it for a good cheekweld and maximum versatility you can just pay like $70 for a railed upper:
and then any competent gunsmith could swap the barrel to that receiver quickly and fairly cheaply. It simply involves removing the gas tube and unbolting the barrel nut from the old receiver, then doing the same in reverse on the new receiver. Then you can flip the loose A2 receiver on gunbroker or whatever and use that money for the optic