They tell me the parts are injection moulded using original dies.
So they took the original molds that had been for the most part, sold to junk, found them, removed the years of corrosion from them (uncoated 1960s tool steel has a really good tendency to rust almost instantly when exposed to oxygen...) and put them back on line?
Very unlikely. What they likely have done is go to China with samples of original bodies, and had a mold company make new molds at a price, and are now trying to recoup their investment by charging more for a new body than a genuine original costs when smartly purchased.
Yes, really cool! 
Just to that you know, when I visited Bill Selzer in the year 1998 in the new Cox Hobbies digs in Corona, the ONLY surviving slot car molds were those of the Supercuc window and roof, the Chaparral 2 and 2D windows and those of the Dino.
REH got them when Selzer sold out to Estes and retired, but after spending a small fortune to repair the Dino windows and get back in production, they did not pursue repairing the others.
All the other molds were auctioned and sold for junk in the 1982 bankruptcy of the Cox Hobbies company in Santa Ana, and as I wrote, it is VERY unlikely that any survived in usable condition. Unused injection molds do not like to be unused.