A mobilization is not a causus belli according to international law, at most it is a cause for your own mobilisation.
The Poles might have ensured that they got the R45 tanks, MS406 and Hurricane fighters and Battle bombers a month early, giving them some more punch. Perhaps all the P.37s would be armed, the P.11G ready and more P.50 produced.
The order seem to have been: 50 R35 tanks, 120 MS.406 fighters, 14 Hurricane IA fighters, 1 Spitfire IA fighter (for evaluation), 100 Battle bombers as well as torpedos, mines, optics and coastal artillery. A lot of this was on its way in September 1939, going by ship to Romania. Some of it was sold to Turkey instead.
Poland is probably going to fall anyway, if the French do not move. Perhaps the Poles will share intelligence with the French and hold out for two more months, allowing the French to occupy the Ruhr area. If the French do, the Germans will have a hard time replenishing their ammunition and supply stocks, which were almost completely drained after the campaign in Poland.
Edit: Added numbers.