I would imagine depends on the specific issue being prevented, but no, its not inherently just the same process with different timing.

For example, with rabies pre-exposure prophylaxis is a series of vaccinations. Post exposure prophylaxis is a series of vaccinations but is a different number of boosters AND (if the person has never vaccinated against rabies before) administration of rabies immunoglobulin

Timing is kind of the defining difference though since it's in the name.