I'd agree that the cyl. head gasket is likely failing - there are oil feed holes on both sides of the cyl. block/head at the front of the engine to feed oil to the front of the camshafts (plus various other oil feeds along the block to feed additional oil to the camshafts). Iirc, there are also 2 small dowels in the block surface (1 front + 1 rear) but I think they're more for gasket and head location than for preventing oil leaks?
But before you replace the head gasket, you might try re-torqueing the cyl. head to the correct torque figure. These 10 bolts are all easily accessible being located between the 2 cam boxes on the top of the cyl. head. Afaik the correct torque figure is 56 ft.lbs. Just occasionally this works (for a while). If you try this, it would be advisable to check the timing belt is correctly tensioned (compare belt tension before and after cyl. head re-torqueing), it might need a slight readjustment (the correct tension is to be just about able to twist the belt through 90* on the longest belt run).
Another possible dodge, providing the oil leak is only small, might be to very thoroughly clean/degrease the affected area plus a little extra to each side and apply something like a line of epoxy resin/adhesive, heat-resistant silicone sealant or similar. - it might help to tap in or remove a sliver of gasket material (e.g. using a narrow cutting disc) to give the sealant a better chance of working. In the bush in Africa, I've tapped in a length of solder or copper wire to try to seal a leak (zero chance of obtaining a new head gasket, suitable sealant or having a cyl. head skimmed where I was located).
I'd agree with all of "bugsymikes" advice but would just like to add - before re-fitting the cylinder head (whether skimmed or not) with a new gasket, please remember to clean out (preferably using a tap, iirc, the size used to be 10 x 1.25mm on the earlier engines but I'm not sure about the '81 model) all the threaded holes in the cyl. block that the head bolts screw into - any corrosion not removed or if the bolts bind when screwed further in due to a head skim may result in the cyl. head not being correctly and evenly tightened despite the torque wrench reading being correct. Neglecting this step often results in a failure of the new head gasket.