The Student Room Group
well if it doesnt say then it's prob TZ0. does it really matter?
Reply 2
Maths May 2004 HL are a bit special...they don't indicate the timezone except that one course code is 511 and one 512. I believe 511 is TZ1 and 512 is TZ2, but I am not totally sure...

I think it is similar with SL and Studies (if applicable, I'm not too sure there were two timezones there), that the course-code ending in 1 indicates timezone 1 and ending in 2 indicates timezone 2.