Ah, you didn't specify that they may be different vintages... AFAIK, the later R154s do have some more robust internals. I do not know of any other differences between USDM and JDM when comparing like years though.
They may not think the transmission is worth a lot or don't have any additional info about it and just need to move it out. The only thing you can do is contact them and ask for as much info as possible.
I've seen them run from as little as $200 dollars up to $500 for a stock one and depending on mileage. A local guy here just gave one away .
__________________
If something breaks or you need to contact a member of the administration please post HERE. Unless it's a private or administration matter please post it on the forum. It benefits no one else if car related questions aren't posted for future users and takes away from the time I'm able to spend helping on the rest of the forum.
If you're so inclined I'm always more than happy to accept tips via PayPal. 
Tip Jar ---> 
|