It's near the changeover from hollow cam to cam with spray bar, and in your picture showing the cam cover removed there's no spray bar but there is the spray bar holder between the two head bolts nearest the chain. I would pop the cam cover off and just double check you can see the oiling holes on the lobes of the cam. You might actually be able to see it oiling when ticking over with the oil filler cap removed.
Here's a pic of a head with the hollow cam - in the centre there is no threaded hole to bolt the spray to (and feed it with oil) and on the right you can just see one of the oiling holes on the cam lobe. Also note it doesn't have the thin metal spray bar holder between the head bolts on the right (like yours does)
If you're not oiling your cam you'll very quickly bugger it and the rocker arms and have to do a complete top end rebuild.