We are not transferring US tanks to Poland - they are getting them new - an export version, M1A2M, which has no classified anything on it - they can stick their own stuff on it. They are currently in production and the first deliveries will be by the end of the year.
IIRC they were supposed to be getting 250 M1A2 Sep3
And 100+ M1A1 that they would upgrade themselves.