That's what I've been told, too.Here is a really neat blog post on this and much more from Horween themselves:
https://www.horween.com/blog/2010/12/14/by-request-whats-the-difference
If I understand what I read correctly I believe that the horsehide used in jackets is almost always front quarter, whether or not that is noted on the label installed by the jacket maker.
Front Quarter Horsehide simply describes the part of the hide that is used. The link above to Horween shows well the break down of the areas used. Horse skins are generally broken down into 3 parts, the Cordovan Shells which sit directly above the horses "butt cheeks", the strips which is a long thin area between the Shells and the front quarters and then the Front Quarters.
The front Quarters are the only area that are suitable for jackets. The shells are firstly too small, also too thick but also too expensive. Shells are mainly used for the very best footwear and wallets. Like wise the strips are also too thick and too small, this area is again used for smaller items such as belts and wallets etc.. This leaves only the front quarters being large enough and thuin enough to use for jackets.
With regards to Aero over the years people have perhaps wrongly associated the term Front Quarter Horsehide to decribe Horweens Chromexcel when in fact all of our horsehide be it Vicenza, Jerky, Battered, Oil Pull and Chromexcel is all Front Quarter.
Going back to the original post there has been the odd ocassion at Aero when we have ran out of "Front Quarter" Horsehide labels and whilst waiting for a new delivery we have had to fit older stock labels saying simply "Horsehide". No mater what the label says if it is Horse then it is "Front Quarter" .........unless we go back to the dark days of Will Lauder and his Storse Era, that is whole other story!!