Pressure relief valve location

I have a 91 gmc sonoma 2.4l and I was changing the oil. I was having trouble getting the filter past the exhaust pipe, so I started attempting to push it up where I could (and eventually did) reach down from above the engine to pull it out that way. While I was doing this, the oil pressure relief valve fell onto the concrete. In my sonoma, there is one single hole in the filte housing bbeing thw filter where it will fit. On the side of the housing, there's another hole it will fit into. The hole on the side o f the housing cannot make contact with oil, so am I correct in assuming it goes in the hole behind the filter? I stuck it in there the first time I changed my oil, but afterwards, my oil pressure dropped to zero at idle. I moved it to the hole on the side of the housing and replaced the oil sending unit, and now on a cold startup, my oil pressure is at 80 (double what it was). I would like to know it's in the right hole be for I test drive it because I'm paranoid my filter will blow off or something.

Behind the filter, I mean.