It is. I do this often as fresh hams (especially) and bellies are not always available in my necks of the woods.
It's best if they are cryo'd. If not, do so yourself, or wrap very well in plastic then use as large a Ziploc as you need (they have giant ones that will fit a fresh ham), press out the air and freeze. (If you have to halve a whole belly to fit, do.)