I looked at one that probably came from a 1997 engine and it's not quite like the parts catalog. It has the mount as an integrated part of the cast aluminum SAI Pump Hose Adapter/Distrubutor Housing. #4 in the parts diagram you posted.
#28 in the parts diagram is a steel piece that mounts the vacuum reservoir. Here it is at Pelican parts for ~$20.
I'm curious to see how your car is configured and exactly what is broken. If the reservoir holds a good vacuum, securing it to the engine with a zip-tie will work fine. Installing the proper mounting hardware will make it correct, but it's not in an easy spot to work on.
If you decide that you want used parts, let me know exactly what you need and I'll give you a good price.
