No. ENTINDEX returns the index number of the entity and INDEXENT returns the entity that has the index number specified as the only argument when calling the function.
Sample uaage:
Code:
edict_t* pMyEnt = ENTINDEX(4); // pMyEnt now points to the entity with the index number of 4 if it exists, otherwise it will point nowhere (will be nullptr)
// Check validity, etc.
// ...
int id = INDEXENT(pMyEnt);
return id; // Will return 4.