Mahogany

My 1986 4x4 has the traditional bed rot; a friend of mine picked up a very clean 1987 bed in SoCal, and I assume there will be no insurmountable fit issues. I told my friend that my '86 has the American style bed and not the Japanese style with the rolled rails...well, lo and behold the '87 bed he got has the rolled rails - he emailed me the photos...will there be any issues with swapping out the old American rust bucket bed for the Japanese style? Any difference in the length of the fuel filler neck, for example?

As a side note, I've been trying to research the history of these little trucks and learned that most of the smaller Japanese trucks of that era were delivered without the bed to save on import duty/taxes/tariffs. My friend that got the bed talked to a guy who used to work in the plant that manufactured those beds. I have not been able to determine if the Japanese style bed was bolted on to the models that have it after the cabs arrived from Japan? The American style beds that were added after arrival in the US are notorious for rusting from the inside out at the wheel wells. Any enlightenment would be appreciated.