Yes you can top your AK-48. I top my AK-47 all the time, and yours is what, just one higher? It all depends on what you are trying to achieve. If you are going for huge colas, then don't top, in fact cut off all your branches except 4 and you will get 4 huge colas. If you are going for yield, LST or top, preferably with a screen. If you don't have much space vertically than top to keep the plants shorter and bushier.