is this normal for oil gauge

[Rwolfe]

I just drove home from work about 30 mins an when I put it in park the oil gauge dropped to L then back up to middle an I have plenty of fresh oil in it

 

[bdmaash]

could be the oil pressure sensor, I did change the sensor on my truck
access through drivers side wheel well

 

[shooterdude199]

the oil pressure sender unit is pretty prone to go out. mine reads no oil pressure at start up but after about five minutes it reads fine.