No, not any sequence ... just those that have 2 underscores
as per your example. By the way, for these files :

abc_1_xyz.txt
abc_2_xyz.txt
abc_3_xyz.txt
abc_11_xyz.txt

Windows Explorer on W2K gives this order :

abc_1_xyz.txt
abc_11_xyz.txt
abc_2_xyz.txt
abc_3_xyz.txt

Not the order you said ...