IOS 12.4 Advanced Enterprise Services willWorking on the 2620xm;if so how much the flash & Dram should be?
The size of the image is the same no matter whether it is in a lab or in production so the requirements for flash should be the same.
You probably do not need quite as much memory to run in a lab as to run in production. But I do not think that it changes the requirement for memory very much.
If your router has less flash or less memory than the requirements stated you could always try to load the image and see what happens. But if it were me I would be reluctant to try to load and run an image on a router that had less than the required resources.