Earlier? Perhaps. I would assume not. Considering US troops actually train very frequently with Poland, have actual QRFs, and have large presence in nearby countries. But let's assume they're early. This still leaves us with the fact the US will be doing the majority of the fighting, the majority of the time. So even if late to the party, a Polish army would see more cooperation on the ground with the US than Germany. Already Germany is giving Poland (and Ukraine) the middle finger.That's certainly true but it can also be pointed out that operating Leos also has its advantages from a commonality/training perspective. In the event of a sudden Russian thrust into Poland, chances are it will be Bundeswher Leos in numbers in Poland before U.S. M-1s arrive in numbers.
The decision to get M-1s was probably driven by a combination of political and operational factors.