Deadeye Cannon: sideways rotation with addon is opposite of game's (v. 6.0.0)

When the Deadeye Cannon is rotated sideways with the addon, actual positioning is 180 degrees opposite in the game, forcing apparent backwards positioning in Blender in order to get it to look right (see attached images).

Addendum: results inconsistent--the issue may somehow depend on the part the cannon is snapped to; in another build, the Deadeye Cannon snaps to the Vesper Diffuser as expected.