I need a query to see if a table already has any indexes on it.
First you check your table id (aka object_id)
SELECT * FROM sys.objects WHERE type = 'U' ORDER BY name
then you can get the column's names. For example assuming you obtained from previous query the number 4 as object_id
SELECT c.name
FROM sys.index_columns ic
INNER JOIN sys.columns c ON c.column_id = ic.column_id
WHERE ic.object_id = 4
AND c.object_id = 4