Catalytic converter assembly gasket identification help

For my '13 prius v, are the gaskets the same on the upstream and downstream side of the catalytic converter section of exhaust pipe? The part numbers i found were 17451 and 17451A(downstream). When I tried to search gasket part on a couple toyota parts online stores, they show up with a variety of different numbers trailing the 17451 number or none at all. Trying to make sure I have they right ones before ordering the whole cat section. Unless it comes with the 17410-37553 catalytic converter section of the exhaust system. Any help appreciated.

 

Thanks for verifying.

Pennsylvania, cars(Light Duty Vehicles I believe) with emission stickers showing California/CARB are required to be replaced with like kind, California/CARB certified catalytic converters or OEM from the manufacturer. Despite being required, not all counties require emissions testing and those that do just require gas cap test and obd2 check. No visual checks required for light duty vehicles. So at your own risk I guess.

I found a Toyota dealer with online parts site to be the least expensive option for buerocratically approved ones.. Less than NAPA and others stores. Even less than the individual cats for welding in place.

The EPA certified cats will do the same thing, just warrantied to 25k miles versus 50k miles of the Cali/CARB certified ones. Our 'free' market at work :-/

 

So oem has specialized manufacturing process/material recipe for the cat exchange material that is potentially patented thereby limited to their use? I would believe that.

Do you know if there really much difference between epa and california cert aftermarket cats or different design & materials?