IMHO the 1601 number is the base part.
e.g. for Set 41710 (the only set which is the BI having this part), the base part 1601 comes with decorationĀ 1019676 and it is now Material ID 6388654
The formed variant isĀ 1019778
e.g. for Set 41710 (the only set which is the BI having this part), the base part 1601 comes with decorationĀ 1019676 and it is now Material ID 6388654
The formed variant isĀ 1019778