For reference:
B13/B14 SR Transmission Mount is NOT interchangeable between A/T and M/T. The A/T has a larger mount and a narrower bracket. The M/T has a smaller mount and a larger bracket. Also, they are at different angles. The 3 bolts that hold the trans mount onto the trans also do not interchange. The A/T ones are shorter than the longer M/T ones. The bolt that holds the mount onto the frame is interchangeable.
B13/B14 GA Transmission Mount (marked MX) is NOT interchangeable with SR ones. GA & SR are at different angles.
You can use the same Prothane insert in trans mount stamped MX or BX.
Transmission Mount:
Auto is stamped BY
Manual is stamped BX
B13 & B14 M/T Trans mounts are different but they are interchangeable.
Thou I am repeating some of what has been said, just adding some more.