I got two 315-5159 MCU's for Shooting Master sent from Brian and Joe.
Decapping both chips worked without any problems and in the end i got good dumps from both chips. Both dumps were identical.
Looking at the driver, both even matched the existing dump of it. Which was marked as BAD in MAME since years.
At least we now know that this dump is good and another "BAD DUMP" flag can be removed.