You should post the question on the GP forum. I am sure Peter can give you all the information you need and more.
I don't know if this particular watch has ETA 2892 base calibre or GP 3000 base, but it does have the chrono module added on to the base, so not an 'in-house' movement. However, if flyback is not a must, you may want to check out GP Vintage 1945 chrono, ref. 2599. In-house column wheel movement, very comfortable to wear, more comfortable than my Grande GMT, and the stree price is quite attractive. A gold one is about the same price as street price of Blancpain flyback in SS and way less than $7k Euro. Search GP forum and you should see pictures of the watch in different dial and metal combination. I am actually waiting for the delivery of mine in YG.