Hi Noyade,
It's a good point and certainly there has been more than one Curtiss Pusher replica over the years.
If ,following on from the Wicki reference , you look up "Lafayette Escadrille" you will see that it was released in March 1958, so probably it was filmed in 1957.
Palen made some money by hiring some of his aircraft out for that film ( The SPAD seems to fit there) so in 1957 at least some of them weren't packed up in "chicken coops."
I think the balance of probability (and the rareness of types like the 504 in the USA) leans towards the likelihood of these being Palen's.
P.S. According to IMDB,
Shooting took place October 19 to December 8, 1956
I've now just realised , reading about the Bleriot "Penguins " built by Paul Mantz, that I saw this film in U.K. as a lad with my father. under the title "Hell Bent For Glory"
(In those days films for me usually fell in to two categories. (i) Films about aeroplanes and (ii) Films that I wasn't allowed to see .
)