37 Flathead Distributor bolt pattern

[AB1935]

Have to excuse my ignorance as this is all new to me. Bought a 1935 pickup, has a 1937 Flathead in it. Noticed some oil towards the front of the engine compartment, cleaned it up and noticed it look as though it was coming from the distributor flange/housing. I checked the bolts and they all needed tightening.There were only 3 bolts but the distributor housing as a hole for a 4th bolt, lower drivers side. Tried to insert a small rod to see if there was a tap for a bolt and I don't believe there is. So my question is are there 3 bolt and 4 bolt distributors? If so will 3 bolts hold this distributor as designed? Thanks for the help.