Hi! Poo are always running 1-2 days behind schedule, depending on how much the guts have slowed down in the wake of the op and reflect the food intake of past days, especially the large gap on the day of the operation.
If a guinea pig can't pass any poos whatsoever, it is going to look very uncomfortable and painful being bunged up rather quickly; if it is suffering from acute gut stasis (the guts have stopped working altogether) it is looking very apathetic very quickly. Either condition is an emergency.
If neither is the case, please continue to syringe feed and be patient. Your feed is going to show up at the other end sooner or later, but there is nothing badly wrong with Presley! As long as he is still cooperating with taking food and water on board, it means that the guts are essentially still working.