GCSE Economics: With regards to exam questions - is the highest mark question 6 marks?

Yes the highest tariff questions are 6 marks. 

For further support regarding the 6 mark question, you may find it useful to see the candidate exemplars which also have examiner commentary.  In the commentary we aim to explain why an answer gets a particular mark and what the candidate can do to improve it further.  For example please see page 7 and 8 of the component 01 SAM commentary.