salaam
there is nothing in the world known as JDM seats , people just like to call them JDM because it has become a trend to call everything JDM that comes from Japan , only cars from Japan are conceder ed JDM then again its an on going argument its up to you what you think .
secondly if you are talking about the bucket seats and considering it as JDM then thats not the proper name for them, bucket seats comes from different manufacture like (Sparco , Bride , Recaro Etc.)
i hope that i have answered your question .
bye.