Bunch of Danish & Norwegian IXe have rounded tails. Just 2 pics of 907 there is some prat standing in the way in one and 41-404 (round tail ) is blocking in the other. 41-408, RK889 (41-420) and 41-419 are all round tails)
SWAG! PT907 was delivered 8MU 26-8-44. 41-419 (RK811) was delivered 6MU 16-9-44 , less than a month later .... with rounded tail. Hardly definative research , but if the newer on had the rounded tail.... 41-422 (RR252) was delivered 39MU 19-10-44. Its what I got to work with......