What was the reason to remove your gall bladder?Simple increased wall thickness cannot be the reason.Were gall bladder stones
ERCP will just see the pancreas
and Common bile duct from the interior.Nothing to worry.It is just like Upper GI endoscopy
where endoscope is passed into these structures through the stomach.
If you come back with the ERCP,i can clarify further.
If you do not want ERCP,you can go for MRCP.
Wish you good health