you can use the drilled bolt and the drip tab for the chain.

it used to be the drilled bolt,then it went to the drip tab with solid bolt.

no reason you cant use both for added oiling of the chain though.

make sure the 2 small oil galley plugs are in the block behind the cam thrust plate,I have seen them get a small hole drilled to help oil the chain also.

IMO,it bleeds to much oil around the plate without the small galley plugs. the chain will get enuff oil from splash and from the drip tab and cut down on windage.

if you really want it to oil the chain,a stock oil cooler uses a hollow fuel pump bolt to return oil back to the pan and spray directly on the chain at full oil psi pressure.

I grab them off police cars when I see them just for that reason and plus it cools the oil.

so..your good with just the drip tab and is the way it would come on a later engine that does not have the drilled bolt for the thrust plate.