No, if you're just moving the IP over, the vacuum pump doesn't have to follow.
Pull the vacuum pumps from both engines and see if they have a basket. If the old one does and the new one does not, pull the IP and basket from the old, install the basket on the new, swap the IPs, remove the basket, and reinstall the original vacuum pump.
The basket will hold the sprocket in place so when you slide the IP into place the shaft will be lined up for you. Make sure you have the locking tool for the timing notch within the IP and make sure both engines are in the right place in time before you begin surgery.
