What BMC said.
Being a 302 it is likely too new. The reverse rotation was used a bunch on twin engine boats for counter rotating props, to cancel out the prop torque. There is overlap, but around 1970 they started making gear boxes that could run in reverse just as well as forward. Now the counter rotating props could be done in the transmission instead of the engine.
I have a reverse rotation small block ford in the corner of my garage right now. The number of parts needed is amazingly small. Cam, distributor gear, starter, flywheel. Flywheel is the biggest surprise, but the chamfer of where the starter gear goes the other way. Would probably work just fine the normal way. The distributor turns the normal direction. If you pull the distributor and look at the helix of the drive gear. If it is wrong from a normal gear, it is a backwards engine.
What brand was the engine boat drive? Eaton and Interceptor had reverse rotation outdrives. I don't think Mercruiser or OMC ever ran reverse rotation in this class of drive. Can't say anything about V-drive or pure inboard engines.
History lesson. The original 302 HO engine used in '82 for the Mustang was a regular 302 (even had the standard 2-barrel carburator) but had the marine cam in it. I worked with a guy that was at Ford at the time. They were discussing making a higher output engine (GM was coming out with the 3rd gen Camaro at the time) and one of the guys (I had his name at one time) told the suits they already have the parts in production. Just put the marine cam in. They listened, they did, and the 5.0 HO engine was born. With nothing more than a production marine cam into a standard 302. It evolved from there, but the start was just a boat part.