well considering i own a tacoma and have swapped the suspension, they're aluminum. they are not the same as the 4R. just like how the front strut and LCA is different from a 4g tacoma compared to the 6g 4R and LC
Patrick at Perryparts plans to offer the bumpstops for sale with the towers and fasteners included I believe for 6th gens. This is probably why they will be more expensive when they release.
He registered to participate in the forum but I do not believe his account has been approved yet.