Old electronics if still working and range tests ok is no problem. In fact there are few still using them as they have all been convinced to go to 2.4. If you never had any problem with your equipment chances are you won't have any now. Big advantage there will be no wait time for a frequency pin as not many will be flying that band. Your battery packs may be your weak link replacing them might be a good idea if your going to use the older equipment. There are several guys still using the older equipment at our club without any problems at all.

Dennis