Hi KLilley,
Thank you for posting your query to us.
You can format those columns to be displayed as currency by addressing them with their index as mentioned in the code below:
this.GridGroupingControl1.TableDescriptor.Columns[1].Appearance.AnyRecordFieldCell.CellType = "Currency";
Please refer the sample in the link below which illustrates the above:
http://www.syncfusion.com/support/user/uploads/cs_6553aff7.zipPlease try running the above sample and let me know if this helps.
Regards,
Janagan.