Josh:  It has been a while since I have done this.  However, I believe you can get to which workflow is being used through the URL.  If not, I can check some notes.

This article might help explain things....

https://www.sagecity.com/sage-global-solutions/sage-crm/b/sage-crm-hints-tips-and-tricks/posts/distinguishing-between-primary-workflow-rules-in-create-scripts

Hope this helps.  :-)

Thanks Michele - While very interesting unfortunately this won't help me in this situation. This only gives the current rule ID rather than the workflow ID, and it is also quite inconsistent when it includes that in the URL. For example if opening the opportunity from the recent menu it doesn't include any of the 'key' values in the URL. 

Josh:  I will take a look at my notes and see if I can offer more.  Also, if you have the current rule id, you can use that to find your way back to the workflow id.

I will follow up with what I find.

Josh:  I will take a look at my notes and see if I can offer more.  Also, if you have the current rule id, you can use that to find your way back to the workflow id.

I will follow up with what I find.

When you initially start a workflow, there are fields that you can be setup to autopopulate the field.  Like oppo_type.  Since I don't know the different types, I will refer to New or Old.

When the initial oppo screen is displayed the oppo type field will contain either New or Old.  You can then use this type to display a field or not using the Values() Colletion.  

At one time, there was an article in the community titled "Display certain fields depending on workflow".  

However, I can no longer find the article.  Hope this helps!

The Workflow ID is basically (in SQL) done as Opportunity (e.g. Oppo_Workflowid) > WorkflowInstance (wkin_instanceid) From WorkflowInstance table you're looking for Wkin_workflowid for the Workflow ID number. 

Though personally it would be better to have the 'New Opportunity' buttons for both workflows flag the Opportunity in some way if it is A or B then in future you just need to query the opportunity record itself to know which workflow it is following.