Replacing main bearings

[Tim555]

I recently discovered a lot of gold glitter after an oil change. The car did briefly make some lifter and/or knocking noise, but that cleared up. There seemed to be sludge in the oil so I changed it. Oil was changed in February by the shop who sold me the car. They used the fram filter, not me. It had maybe 1500 miles on it. Cat has 94k. This what I found. Can the mains be changed from the bottom of the car if the crank journals aren?t damaged?