Expression of the year

I feel the specification is ambiguous about the expression of the year.

In the problem description, it just says '01' in the year part means 2010. In the fourth test, the header start with '0807101010101061' and expected decoded timestamp is '01 Jan 1970 01:01:01 GMT +4'; '07' is decoded to 1970.

I think that means sufficiently large number for the year part stands for 1900's, but the threshold is not clear.